Yeah, it's a hard one. It might help to let people know to avoid dealing with them.
I had a issue with a member on here many years ago, basically he found a mtb at a recycling centre and wanted to know who wanted it. I called dibs but only if he could post, at my expense of course. No problem but would take a few weeks to sort, get a box etc. All good. he got a postage quote as we live at opposite ends of the country, all fine, I paypal gift of twice that quoted so he could get a few beers in, he was happy I was happy as it was still a bargain for what it was. Bike never showed up, after a couple of messages he was not answering and eventually was no longer 'around'. About 18 months later, if not longer I get a message saying sorry but a lot of 'life stuff' got in the way and it just slipped by the wayside. By then I was well over it and beyond thinking of it, just chalked it up to one of those things and hoped he was now in a better place. It was only a bike that I never had anyway so told him it's all sorted, thanks for the apology and forget about it. He then messaged me and said he still had it in his shed and would like to get it boxed and sent to me. Never heard anything for a while, and he was back on the forum regularly so just dropped him a line and asked where we were up to etc only to be told 'sorry, I sold it' No offer of refund of a decent amount I had originally sent, nothing, end of. So never assume that everyone is as upstanding as yourself and never use paypal gift, unless it is somebody you know in the flesh or have dealt with many times. The majority on here are brilliant people to deal with, it is like a club, everyone helping each other out. Though there are a few who take the p, and those who are just not malicious, but just shouldn't be selling as they are way too casual.
Jamie