This guy PM'ed me today as well with the offer to exchange my PayPal to his BTC. I went first ($79) and he said that he had a problem with his PayPal, so he refunded my funds. It doesn't look like he is scammer.
Did you can post a proof about refund has you got so it's like something weird for me OP said get scam for $20 and you said blackheart13 has send back your money $79 or you is same person with blackheart13.