Bad quality gold studs

My boyfriend bought me a pair of gold studs at the American Swiss store in Sandton on 15 May 2015. Disappointingly they started tarnishing after two wears, took them in to the sandton store with my proof of purchase, Lethu cleaned them in the solution told me it was my skin acid or make up that was maybe causing them to tarnish.Left the shop and told her I will give it another shot and if they tarnished again I would return them back for a refund or a swop as I was not satisfied with the quality. Was told as long as I have proof of purchase I would be assisted as its a quality complaint. Visited the shop on Sunday 30/8/15 to be met by an attitude from a lady called Chatlotte who started interrogating me with questions in front of other shoppers who were staring at me it was so uncomfortable that I decided to leave the shop because I just couldn't handle the way she was so unprofessional in her business dealings. I am not happy want a full refund for these bad quality studs. She told me that these won't ever be taken back but is it my fault that this product is of bad quality? What ever happened to the good old customer service? Shocking!!