How can I get the most money from this jewelry purchase gone awry?

8 months ago I had the brilliant idea to get a mothers ring commissioned for my mom. I was so certain that my 2 siblings would help me pay for it, but because they haven't wanted to or been able, I just haven't been back to the store, feeling foolish and impulsive having to explain to them that I had ordered something I should have thought through better and now don't want at all. I put $500 down which was about 1/3 the cost of the ring. I still have all the receipts, and it clearly states that after 30 days or on any commissions, that any deposits are only available towards store credit. I really need that money back now, so my question is: what can I get from the store that will have the best resale value, or any suggestions on how to turn this mistake back into actual money that I can spend on something else.