If your buyer is not willing to meet you at the location and time that you chose whilst listing, please try to make an alternative arrangement with them that suits both parties. If you are unable to do so, you are in your right to refuse to refund the buyer as they should not have purchased the tickets if they could not meet you at the location and time stated. 

If you cannot meet with the buyer but you would prefer to sell the tickets to somebody who can use them, please issue your buyer with a refund of the ticket costs only via PayPal (do not include the buyer's fees). You can then re-list the tickets for sale in the same way as before.