Getting seller help from ebay

[n10d1]

Can anyone tell me how I can get help from Ebay? I have been a seller for over 10 years and have 100% positive feedback. I recently had a buyer that purchased 3 items from me, 1 of which was a white gold chain from me and I accidentally sent him a white one instead. He requested a return/refund of which I of course agreed to but as dumb as this sounds I mistakenly gave him a credit prior to him returning the chain. He decided to keep the chain and told me that he wasn't going to pay me and that there was nothing that I could do about it. I contacted Ebay by email to no response and then by phone and they seemed less than motivated to try to help me and went so far as to tell me that I could pursue the matter outside of them if I wished. The man freely admitted in our ebay email correspondence (of which of course ebay could read) that he knew that he was stealling $175.00 from me but that I couldn't do anything so he was keeping the money! I had my lawyer send him a letter but he still refused to pay. THEN, after 5 weeks (my return policy is 2 weeks) AND after leaving me positive feedback he opened a case for the other 2 items and i was forced by ebay to accept the returns AND pay the return postage! I simply cannot believe that ebay would allow someone to flat out steal, knowingly and admittedly and do ABSOULTELY nothing about it. Is there anyone that can help me in this matter? Any suggestions would be greatly appreciated. 

DR