He apparently added the wrong skype account and purchased an account from the impostor. If I sold him an account he would of left me a vouch. Hence why he is banned.
I suggest filing a report with the proper evidence, the fastest way to get something done. If he refunds or gets banned either one will happen a lot faster with an open report against him. Waiting for him to handle it himself is probably just going to allow him to stall for a fair amount of time and potentially scam other users.