I don't know much about your situation, but I can try to help you out.
For your first question: In your inventory, scroll down to the avis folder and right click it. It should give you a drop-down list. At the very bottom of this list, there should be 4 options; "Wear Items", "Add Items", "Replace Outfit", and "Take Off Items". Select the "Replace Outfit" option, and it shouldn't look at all deformed. (I use the Phoenix Viewer, so it may be different on the Viewer you use.) If it still isn't right, then contact the creator.
For your second question: Contact the owner of the shop you bought it from and tell them exactly what happened. They will more than likely be willing to refund your money for the second item bought, and send you a copy of the avatar you never received. I had a similar problem before with an item never being received. I bought an item on the Marketplace and I teleported before I got the item. Needless to say, it never arrived. I contacted the shopkeeper and they were very understanding.
I hope this helps you out :matte-motes-bashful-cute-2:
~Nix