Buyer has paid but won't arrange collection

[unico_rocks]

I'm not sure what to do. 
I stated very clearly in the listing that I am moving house and the item (a large freezer) had to be collected by a certain date. 
The buyer has paid but is ignoring my messages despite me repeatedly telling them that they must arrange collection with me. 
What happens if they never return contact? 
Will I have to refund them?
Very frustrating as I obviously don't have time to sell it again now, but if they never collect it I can't exactly keep the money. 
What do I do? 
I've been through eBay's help centre but there is no area that would cover this!

[redwick1]

It is difficult if they have paid.

You could contact them once more and ask if they wish to cancel

It was not a cheap item so they would want their money back

If they do then you can cancel Buyer requested to cancel and then refund through the case.

I would try that first and see what happens

[unico_rocks]

So I contacted a few more times, mostly ignored, but then told that they would arrange collection when they're ready. I emailed one final time this morning and let them know that if they didn't arrange a date/time for collection with me in the next 24 hours I'd need to refund them so I have time to dispose of the item before I move house. Now they're sending me abusive messages calling me a bully and saying I'm racist? I've refunded them, but they're continuing to message me. How can I block them?