Certainly contact trading standards, but I wouldn't hold out any hope of getting your money back and I wouldn't expect much help from Paypal either. Going on the experiences of a few people I've spoken to or heard from in forums, they really couldn't give a toss.
As for what they called you, don't take it personally (because you know it's just not true), tell them you're going to take them to court and threaten them with the BBC. Maybe you don't plan on doing either of those things, but it sometimes works and if it doesn't, then do it anyway. I'd also let Man Utd's marketing arm know about them, as well as any other clubs whose gear they claim to sell, because even if you feel you can't prosecute, the big clubs will have no such qualms.
And for the future, remember the consumer's mantra - if it looks too good to be true, it probably is.