The former couple had met at the offices of Laura Wasser, who is representing the 30-year-old sock designer, with their legal teams in a bid to iron out arrangements for their nine-month-old daughter Dream but it seems things were not entirely amicable as, after spending hours inside the building, Chyna tried to take off in her ex-fiance's Range Rover.
Sources told TMZ Rob had had someone called ahead to have his vehicle taken to the valet stand, but he wanted to wait until 29-year-old Chyna had left the building in Century City, Los Angeles.
However, the ''visibly agitated'' star care and saw the Range Rover, so got inside the car and prepared to drive off, but was warned off my one of her lawyers, who said: ''That's not a good idea.''
The lawyer and a valet then got Chyna - who also has a son, King Cairo, four, with former partner Tyga - out of the car and away from the situation.
Chyna's lawyer, Lisa Bloom, told the website Chyna didn't get inside the car or try to drive away, but she admitted her client was ''agitated'' and had some ''choice words'' when she saw the vehicle because she had given it to Rob as a gift.
Rob gave Chyna a Ferrari and a Lamborghini during their relationship, but while she gave them back after they split, the 'Keeping Up With the Kardashians' star held onto his Range Rover.
The lawyer admitted they had made no resolutions during the meeting, and so a planned legal hearing will take place next month.
She also said she would be raising allegations of domestic violence against Rob.