I sold an item today on an Auction and the buyer paid for it. When I went to print out the label I noticed it wasn't a full address, just London and Postcode. Then received a message from buyer saying please can I add a flat number to the address. They have 0 feedback. I thought this was dodgy so asked them to edit the address their end which they said they failed to do. I refunded the payment but now can't cancel the order - I presume I should've cancelled the order first but is there anything I can do to remedy the situation?

Thanks in advance for your help.