A4 B8 2.0tdi tensioner failure

I bought a v-belt tensioner for my A4 2009 2.0tdi on 06/09/2021 and in September I encountered that the tensioner was giving out a lot of clicking noise. I then informed Goldwagen by email about my 3rd bad experience with their tensioners same as their v-belts for this model. They informed me to book in the tensioner for a test. After booking in the tensioner, I had to force communication via emails about thd status of the test. Their representative known as Melvin, called me and told me that according to their mechanic or manufacturer if still correct, the issue is usually a result of a failure of an alternator clutch pulley. I immediately informed him that my clutch pulley was changed around 2020 December so it is fairly new and it is still working fine because I tested it. So 3 weeks down the line, they refuse to exchange the tensioner today saying that the knock and the unpleasant sound coming from the tensioner is beyond their control. When I put back an old tensioner on my tdi, no noise comes out but when I put their then suddenly a knocking noise comes out. Their report suggests that one of my clutch pulleys could be causing the problem whereas only one clutch pulley can do such and that can only be the alternator clutch pulley but on my car, the alternator clutch pulley is very new. I also tested it it works fine. The only thing that was not new, was the A/C clutch pulley. That was tested and found to have no problems even with thd old tensioner put back on. Goldwagen plays a lot of tricks so that they do not refund customers.