AUDI A5

My car keep on cutting out completely so I took it to Audi on 17/06/15, I received it back on 24/06/15 with an oil leak which was repaired with silicone. The car went back, I received it on the 03/07/15 with a huge engine noise. Since then they been struggling to get to the problem of the car. I received it on 30/07/15, just for the car to breakdown the following day with exactly the same problem it went in for on 17/06/15, cutting out while driving. I have report the matter to Head Office per e-mail, which I did not even had a phone call. I really now need assistance in this matter. I have an e-mail which I send to Head Office if you want to read the whole story. This is just short, because this car gives problem since the day I bought it in February 2013, with the same problems all the time