Mariah Carey and Nick Cannon*Ongoing divorce negotiations involving Nick Cannon and Mariah Carey are heating up.

Sources tell People that despite the couple’s best efforts to keep details of their situation private, behind-the-scenes is a different story. The most recent example of this came last week during the Rockefeller Center Christmas tree taping. Carey stood up fans who came to see her perform at the event by arriving three hours late. The reason for the Carey’s tardiness stemmed from her discussing the split b on the phone with her divorce lawyer.

“She was on the phone for probably close to five hours straight with lawyers,” a source told People, which noted how unhappy fans were with Carey for leaving them to wait in the rain.

“She would never want to upset her fans,” the source added while insisting that Carey and the lawyers were “arguing over property and custody of the twins.”

The divorce discussions are the latest developments since Cannon and Carey confirmed their split in August. The couple, who welcomed their twins Monroe and Morrocan on April 30, 2011, were married on April, 30, 2008.

At this time, there is no comment from Carey and Cannon’s reps.