Well, we don’t know the circumstances around the pinkbike ban do we, it could be a very similar case to this one with a single complaint, or it could be months of abuse, we just don’t know…
As Yunki said, would be a very odd turn of events for a regular poster like that to suddenly attempt to pull a fast one for such a small sum.
Could be you both paid, and he emailed you both back not realising you’d both paid for the same item. I’ve actually done that one myself in the distant past when I had several things for sale at the same price and received multiple payments of the same amount, then realised after reading emails I’d apparently sold the same thing twice when I thought they were for different items. Factor that in with the sudden abrupt end to his postings and could be a lost phone or something…
I know on the face of it it looks grim but give the chap time to respond before you lynch him.