So I see things via the Facebook market place. Just odd bits n bobs we don't use. This afternoon someone messaged to ask if the item was still available. I messaged back to say yes, they asked if I'd take a fiver less than asking, again, yes. Arranges to collect at six, I send him my address and then never shows. I assumed I had been blocked but my friend did a search for him and it looks like he's removed himself off Facebook. Is this just really odd behavior or should I be concerned?