She's happy enough to flash her cleavage, but Mariah Carey is shyer about opening her checkbook, according to her former manager.

Jerry Blair, who also served as president of her MonarC Entertainment, claims the diva has refused to fork over major money she owes him, sources tell us.

Blair was the man "who helped Mariah make history when she achieved her record-breaking 15 [No. 1] singles and most consecutive weeks at [No. 1]," according to a 2002 announcement of their now-defunct label.

"Jerry stood by Mariah through her breakdown," says a source. "He believed in her when other people lost faith."

But once the "Emanicpation of Mimi" songbird was back on her feet, "she ditched him," a friend of Blair claims. "She wanted to distance herself from anybody who saw her in those dark times."

Blair contends that, under their agreement, Carey still owes him a cut of her record and tour profits, according to sources.

"She hasn't paid him in two years," says an insider. "He had to call in lawyers."

Friends of Carey suspect her ex-husband, Tommy Mottola, was behind this new blight on her happiness. "Jerry and Tommy fell out when Tommy was his boss at Sony Music," says an insider. "But they're working together again at Casablanca Records."

Friends of Blair suspect Carey has been stonewalling on the advice of her label boss, Island Def Jam chief L.A. Reid, who clashed with Blair years ago at Arista.

But another source insists, "This has nothing to do with Tommy or L.A. Jerry just wants to be paid."

Earlier this summer, it looked as if a settlement was at hand. But a source says, "In the past couple of days, the talks have broken down."

Blair and his attorney declined to comment. Carey's lawyer and publicist didn't immediately return messages.

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Kanye West and 50 Cent are still nursing their pseudo-feud. Two weeks after they supposedly made up on stage, Fiddy told a radio interviewer: "Kanye sucks … He sounds like a robot." A snitch laughs: "This whole thing is concocted to help drive sales" of their two CDs, which both drop next Tuesday. Another source tells us Kanye is planning to attend 50's Absolut 100 album-release party in Vegas next week following his Pontiac Garage performance.

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Sean Combs and estranged girlfriend Kim Porter kissed and made up (at least for Labor Day weekend) at the rap mogul's "Real White" party on Sunday. Though Porter angrily ran off to L.A. with their twin babies this year, she returned with the kids for the annual bash at his East Hampton estate. "Diddy and Kim looked very lovey-dovey," standing on the balcony, where he had once kissed her rival, Jennifer Lopez, a spy tells us. "We'll see if Kim can stay strong." Also at the party were Donna Karan (who took a spill on the dance floor), Lil' Kim, Mariah Carey, Busta Rhymes, Tommy Lee, and Star Jones and Al Reynolds.

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Anybody who needs some posh presents for a new baby might want to check the trash outside Bridget Moynahan 's house. I have a feeling there's some great stuff in there.

A rep for Petit Tresor, an upscale children's store in Los Angeles, confirmed that her estranged baby-daddy, Tom Brady, had phoned in an order.

His new girlfriend, Gisele Bundchen, paid for a separate order in the same phone call. Included in Gisele's $1,000 gift basket was a onesie with the word "supermodel" written across it.

Which is exactly what you want when your boyfriend leaves you for a Brazilian supermodel just after you get pregnant. Tactful!

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Zac Efron and girlfriend Vanessa Hudgens may be the hottest teenage couple of the moment, but they have a practical side.

A source tells us the "it" kids stopped by Chicago's Neiman Marcus on their promotional tour for "High School Musical 2" during the last week of July.

Vanessa picked up a $1,200 pair of Rene Caovilla heels, which Zac paid for. (Awww!)

But an inside source confirms the shoes came back the next day, after a night on the town.

"These shoes weren't gently worn. They were all torn up like she was dancing all night," says the snitch.

According to the insider: "Department stores call those people ‘the renters,' who return the stuff the next day. It's unusual to do it with shoes, though."

Hudgens' rep did not comment Friday.

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DINA Lohan's new boyfriend has fired back at Michael Lohan for calling him a boozer unfit to be around his kids. Jim McMillan, in an e-mail to Page Six, calls the troubled father of Lindsay Lohan a violent, drug-abusing criminal who never deserved his "classy, intelligent" ex-wife.

Last month, we reported that Michael had his lawyer write to Dina, complaining she had shacked up in the family's Long Island home with McMillan. He charged McMillan gets drunk around his youngest kids - Michael, 19, Ali, 13, and Dakota, 10 - and makes inappropriate comments. "He is no example. Nor is he a substitute father," Michael told us.

In a scathing response, McMillan rages: "First and foremost, I am a gentleman. I have never been inebriated in front of [the children] or said anything about a man I know nothing about. I did decide to learn about Michael Lohan and did a quick background check. The following is public record, fact and irrefutable: On 10/13/84, you struck, choked and kicked Susan L. Hubbard of Ohio, causing fractured facial bones.

"In [New York], there are 10 arrest records found for securities fraud, DWI, assault, grand larceny . . . Dina has never been arrested or charged with anything."

McMillan then addresses Lohan directly. "Upon getting out of jail, you hire a publicist and start a smear campaign against your children's mom. You take a photo of her holding a water bottle at your daughter's premiere, and you call her a party mom. You . . . accuse her of being an alcoholic, a drug user, an unfit mom and a philanderer.

"You do it in a very public way and force them to deal with the fallout. If you want to assassinate someone's character, leave Dina alone. She is way out of your league. She is a classy, intelligent, loving mom . . ."

Finally, he urges: "Work hard, support your children, stay clean and sober, privately make amends for the physical and psychological abuse you have inflicted in the past, so your children can have closure."

Dina and Michael recently finalized their divorce and custody issues, and Dina lobbied Lindsay to allow her father to visit her at a rehab facility in Utah.

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DAVID LaChappelle is the go-to photographer for pop stars wanting to reinvigorate their careers, but the list of ladies he'll work with is dwindling. LaChappelle, who loves Pamela Anderson and Courtney Love, refuses to work with Madonna, Gwen Stefani or Christina Aguilera ever again. "He hates them," our spy said. "Something weird happened the last time he worked with Gwen, and he has cut her out." When Jennifer Lopez wanted him to work on her latest video for "Do It Well," the source added, "She had to call him personally. It worked out well. He loves her."

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Brad Pitt as you've never seen him - shaken up as a frenzied female fan makes a lustful lunge for the usually cool-as-ice star at the Venice Film Festival in Italy. "It was a scary moment," one witness said of the instant Pitt fall into the arms of the woman, who beamed (inset) even as the actor's security goons yanked her off him. "[Pitt's] security team must have been embarrassed that she was able to get that close to him," the onlooker told The Daily Mail of London. "She could have been anyone. Brad didn't look happy about it at all."