Haven't had this before and wondered if it was a scam? They have refunded by the look of it but hasn't reached bank yet and is 50p short of what i paid. It might be totally innocent and I'm just paranoid.
"Hiya, i am sorry I've put in my wrong bank details for payments, I've tried to amend the listing to try and sort the issue out but I can't seem to do so, I have managed to refund you so that should be complete soon and I haven't cancelled the sale so I'm able to send a PayPal invoice from the item and it will go to your PayPal account to pay again if you still want it, I'll need your email please, I hope this is okay please let me know x"