I want to cancel an item a buyer bought because he failed to meet the time specified for pickup. HE IS CAUSING TOO MUCH TROUBLE!

[vortex_co]

I sold this item on eBay. The buyer before asking me any questions, bought the item then started asking me question of i could deliver, that i should be able to because they dont live far away, then they said it was wrong size but then they said they will take it. It was a big hassle. Then we organised a time for them to come at 6pm, the location was an hour away from where wer live and my dad had to leave work early. They then notified me once at the location they couldn't make it and they will come tomorrow. Now these people are trying to set their own rules, and me and my dad have wasted so much time. We sent a request for the transaction to be canceled and they denied. They threatened to give me negative feedback and file a complaint. What can i do??