Car issues

I bought my car with a Gold sticker and the sales person assured me that the car has no issues and everything works well. After collecting the vehicle it had a strange knock on the passenger side under the car, I reported the matter and it was taken to one of Webuycars workshops and so many issues were discovered gearliage, battery and so many things which were fixed. September I took my car to to replace my tires, break pads and also CD Disk and I was told that my car sound it’s not normal and it’s not suppose to sound like that, it has cambelt chain issues and underneath my car there oil build up. I didn’t taste drive because I stay far from the branch so I had to trust the sales men and the dekra report as they mentioned that you will never go wrong with reading the dekra however the system failed me really.