The small claims court holds no terror for you It takes place in a small room with you, them and a judge in a suit. The other side often doesnt bother to turn up. In which case yoyu win, so TURN UP. No legal eagles allowed. Documentation is all important and vital, so it must be complete. Phone calls are fine if a record is kept and agreed (it rarely is agreed) so stick to letters, including, "confirming our telephone conversation of today...." or "confirming our e-mail correspondence, copies attached....". You can see that real letters are best. The judge will say "I have read your corrspondence, have you anything to ADD", don't waste his time if you've done the job right only later correspendence or contact will be relevant. He will then say the same to the other side. Then pronounce judgement.
I did quite a few in my previous job, I doubt if the procedures have changed, only the amount involved to be eligible for small claims. There is of course no appeal because you both agree to accept his judgement. All very civilised, especially if you win, but you can only lose the fee paid to enter the claim, because Audi have no claim on you.
Remember to claim against the relevant party, not Audi, they didnt sell you the car, but their comments are valid if they make any.
Good luck.