Poor quality and bad client service

My fiance and I went to purchase rings on the 17th of December and unfortunately mine started to tarnish 1 week and a few days later. We went back today with the proof of purchase and we were told that they won't give me a refund and that I would have to wait for their work shop to open on the 11 th of January so that I pay for the repolishing that's the only time they can take it back because it's my responsibility to make sure that the ring is in perfect resale condition before they can refund me.