Tata Motors — Nexon front disk

I have done my second service for my Nexon recently and from then front tyre disk started rusting. That rusting remains same even if I drove vehicle for more than 500kms. I'm pretty sure my vehicle is not prone to any water and we don't have any rains aswell. I sent all the pics to that servicing center but till now I didnt get any response. I have never expected this quality from one of the top Indian car manufacturer.