Having a problem unlocking the audi r8 in midnight club los angeles?

I finished all 12 of the challenges to where they each say 100% but it says i have only completed 4 challanges on the A class B class C class liscense thing. how can i fix this to where i unlock the new rims and the audi r8?Having a problem unlocking the audi r8 in midnight club los angeles?i unlocked every car by just getting a motorcycle fully upgrading it. and then doing the orange highway races, makes bank and unlocks cars fast