I always use a credit card, never my Tradesy Balance since I know there are scammers like this around. I know tradesy will cover me though, it should be so clear that I just bought the item late today to only have tracking show "Delivered" on October 1st to a completely different state. Bad scam once you look at the tracking LOL!
They need to come up with a better system/enhance the one they have. One reason I like Posh is because they send you a label and you have to use the one they sent to have funds released.
ETA: Stephanie just posted another bag, this time MK. Hopefully another buyer will not fall for it.