Am selling something on a FB site. I get a message asking me if item still available to which I say yes. They say they will purchase and ask for my PayPal details, which I give. I then get an email 'from PayPal' saying my payment is on hold as the money has been sent from a business account and I need to receive another £50 and then refund this £50 and pay another £50 myself back to the buyer in order to qualify for a business account. At this point I tell the 'buyer' that I'm not sending them £100 because how do I know this isn't a scam? (There is no payment showing as pending in my account).