Sold a collection only item two and a half weeks ago. The buyer paid by PayPal and arranged to collect it the next day but nobody turned up. I messaged them and they said they’d come the following day, again nobody turned up. I then didn’t receive any messages from them until this morning when they asked if they could come ‘today at some point’ 
. I’m not in today so I explained that tomorrow evening would be better, they haven’t responded!
Tired of the flakiness at this point and wanting to cancel the sale and refund them but can they leave me negative feedback if I do this?