I haven't traded much on Neopets but I do remember this one annoying tramp of a girl who tried scamming me out of the money I paid her for a collectible once. She'd been around at the forum since before I'd even signed up and she had a perfect track record so a lot of people would regularly purchase things from her, except apparently it was all just a ploy to gain our trust. She finally hit the jackpot (one user sent her about 500 bucks worth of merchandise to sell) and she took off and ran with it. I was lucky because it had only been a week since I sent her the money through Paypal and I was one of the first to notice that she was acting oddly so I filed a claim early while there were still funds left in her account. The person who sent 500 bucks worth of stuff wasn't so lucky. :/
I'm so sorry that happened to you. This is exactly the reason why I don't feel like playing legit anymore, I'm tired of having to fear that any one little mistake I make means I get the banhammer. Neopets is stupidly strict and uncompassionate with how they deal with people who aren't even trying to do anything wrong.