User Activity

When I contacted the buyer with postage costs he said his account got hacked and he didn't bid on the item I sold. I want to cancel the sale.
I have seen a listing for an item and it looks like it has been reposted numerous times in the one catergory. So far I've counted 5 times over 5days and all are active .Is this allowed?
I purchased outdoor lights but when I opened the box there was no transformer. It clearly shows on a picture in the listing of box contents '1 x low voltage indoor transformer' These lights are useless without it.( I can purchase one from the manufac...
Just out of curiosity, can someone trade using multiple user names?Found two listings that were near identical but with different user names. Just wondering.