I'm wearing a box! I paid for some item(s), but all I got was a prim. What's wrong?
Did you check the box's contents? In many cases, a vendor sells you a box that contains the items you paid for, which may include clothes. You need to unpack the box and wear what's inside. See this video tutorial about selling and opening boxes for more detailed information.
If you paid for an item and really got an empty box, you need to resolve your disagreement with the seller on your own. Linden Lab cannot verify, enforce, certify, examine, uphold, or adjudicate any oath, contract, deal, bargain, or agreement made by the Residents of Second Life.