Unique Jewelry - Rip-off

I recently had an unpleasant experience with this store.  I took some diamond earrings in to have the postsa replaced.  The lady in charge asked me to pay in advance, which I did by credit card.  When I came back less than a week later to pick them up, I found out they did not record that I had paid in advance.  Unfortunately I did not have the credit slip with me (it was extremely small and I may have thrown it away assuming of course that they had recorded I had already paid for this repair).  She would not give me diamond earrings without me paying for the repair twice (approximately $150).  I asked if I brought in my credit card bill when I received it, showing the double payment, would they reimbuse me and she said yes.  

Unfortunately when I took in the credit card bill when I got it, about 10 days later, she refused to reimburse me.  She accused me of maybe making a second purchase.  The two charges were different by about $20 since I also had purchased some other earring backings the first time.  I asked her to check her own records to verify what I purchased and paid for and she refused to do this.

Be aware if you shop there to "not pay in advance" for repairs.  Not only am I upset by the double charge but more by the lady manager's attitude toward me.  I can't believe this store is that busy and that their record keeping is that bad that they could not track my initial payment to determine I had already paid for the repair as requested up front.

Has anyone else had similar problems with this store?