Jason DeRulo posts bill of sale document as ex accuses him of leasing gift BMW

Former couple Jason Derulo and Jordin Sparks' split has started to get nasty after she alleged the car he bought her was actually a lease - and the No Air singer has been dumped with the payments.

Sparks took aim at her ex in a recent radio interview, insisting the BMW he gave her as a gift during their romance wasn't paid for.

DeRulo has now fired back at the singer on Instagram.com, posting a grainy photo of the purchase document and adding the caption, "Women Lie, Men Lie, Numbers Don't Lie!"

The vehicle bill of sale image clearly shows his full name, Jason J Desrouleaux, as the buyer and the price, $74,431.22 , as well as the dealer's fee.

In her interview with New York radio show Power 105.1's The Breakfast Club, Sparks claimed she didn't realize her ex had allegedly leased the luxury vehicle until she attempted sell it back to the dealership.

The couple split last year (Sep14), but initially insisted they would still be friends.

DeRulo dismissed reports suggesting his infidelity led to the break-up and, despite the BMW mix-up, Sparks insists she still can't bring herself to hate her ex, stating, "He's a great guy. I don't wish him any harm. He did some stupid s**t, but I can't hold that against him."