If the seller is a serial scammer, pretty sure he had faced plan B and plan C before. And to be honest, those plans are useless to scammers, and this is why there are still many scammers around in this country.

But since you say you have this fb and his family details, maybe you can add his family members as friends, and start explaining them the whole story. Maybe (yes, only maybe), he would succumb to family advice/pressure and you can get your money back.