Grate on the brake discs

Hello together, 2 weeks ago I had my summer tyres put on (not at my Audi dealer but at another workshop) The workshop pointed out that there was a strong rust on the brake discs, which I should urgently complain about. I bought the car in February. After it was on the TÜV report “Rost on the brake discs”, I told my dealer that this would “brake away” after a short time. (Flugrust by standing time outside) ) – probably did not happen Since my Audi dealer is in another city I can only have this checked in 2 weeks on site. (the Audi dealer on site refused?!) Do you think I have chances to have this done on warranty? – I have my wear parts like brake discs are not covered by the used car warranty. I assume my problem with the vibrating steering wheel when delayed from fast driving, which I had reported some time ago also comes along. no for your opinions!