Ring Colour Coming Off

Very disappointed with my purchase at American Swiss. My husband and I purchased our wedding rings two months ago and got married the weekend of the 13th August. Only started wearing my ring then and on Monday I realised the colour of the ring was turning brown. The very same week on Wednesday I took it to American Swiss clearwatermall. I showed it to one of the employees and she took it to the back and "cleaned" it. She told me the ring is Rhodium plated and bound to tarnish. I was not told this information before purchasing. She then assured me that she cleaned the ring and it wont happen again. It has since gotten worse! I am walking around with a ring that has brown patches. This is an inconvenience since I already showed family and friends my ring. And we took pictures with the same ring.

I want this to get sorted ASAP. Preferably would like to get an exchange and get a ring that wont turn brown!