I've had that issue with paypal, had to post some id and a bill with my address on it to them. Never trust anyone you haven't dealt with before, we've had a long serving member on here flip and do a runner before, it can just be down to a change of circumstance that leads them to do it, but bear in mind its very hard to screen Facebook with so much traffic. Which is why you should always send a payment as goods/services unless you either can afford to loose the money or can 100% trust who you're dealing with