unfortunately, anything is possible in this matter. it is possible that he is saying the truth, and it is possible that he isn't. either way, this is just part of the issue with transacting off an exchange through someone that is more like a third party, the transaction is just based on trust and nothing more. regardless the advice you get on the forum, it would do little to no serious help as your friend is not a part of the forum.

the buzz that is associated with the PI listing will bring up a lot of issues and while some will gain, others will get scammed. it is just the usual and only unfortunate that you are the victim. the simple lesson to take from this is that, when you are too desperate for things, try and be calm and don't rush into things under pleasure. also, doing things yourself is the best way to go, had it been you were directly involved with the buyer, you should have known if it is the buyer that has scammed you or not.

let's not always be too quick to shout Nigerians at the slightest scam incidence. anyone can scam you and it is possible that your friend is telling the truth and actually got scammed by a foreigner he did the transaction with. one man's error is not enough to paint a whole region black.