Hallo,I need HELP,I just recieved snare drum from USEbay

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEBTOX:IT&item=350009271104&_trksid=p3984.cTODAY.m238.lVI

It was listed as 6,5" deph, but seller measured depth with RIMS ON!!! So real depth is only 5,5" witch I didn?t bid on. Of course, seller doesn?t want to refund my money. What would You advise me to do? How could I forced him to refund it. Sorry for my English, I do my best. Thanx. peter Help2