Well, you're doing the right thing but I must say, if you're trying to show the deformity/damage, these pics don't really do it. If you bought this from a rated reliable seller on EBay, I would contact EBay right away and send them the pics of the original fish purchased and the one you received with the damaged tail area. Tell them what's going on. This seller is blowing you off possibly because the original fish has an infection (along with probably many others in the same tank) and would be obvious to anyone that it was their fault. They're buying really cheap quality stock, probably from Blue Ridge or Blackwater Creek and trying to market them falsely as being something rare/exotic/special to jack the prices up to unsuspecting buyers new to the hobby. Keep at it until you get retribution.