Megatronics Problem with Audi A3 Sportback 1.8T

On the 17th of August 2015 my Audi A3 gave problems when selecting the drive mode of the vehicle. The vehicle would not move forward at all. This is when I knew the problem that started in October 2014 deteriorated and stopped functioning. I was so upset in the mere fact that I took the vehicle to Audi N1 Centre in Goodwood on the 17th October 2014 and asked them to investigate as I was not happy. They logged a job card number 73011 (mileage was on 90012). The vehicle was returned to me the same day and the diagnoses was no fault found. I knew there was something wrong and were not happy with their findings. Prior to the Megatronics malfunctioning Audi N1 Centre replaced multiple clutches on the vehicle, this meant removing and reinstalling the gearbox. This was done in August 2014 (refer job card nr 70528 (mileage at the time was on 83145) On the 29 October 2014 I also booked the vehicle in, refer job card 73341 and mileage at the time was on 91221. This time they did basic settings & adaption on gearbox.Audi Centre N1 quote me R37632 for the replacement of the Megatronics Unit as the car is not in a warrantee with them anymore, i should not be liable for any cost to repairs.