Being blackmailed by a crook

[dr_johjo_k2ob2l8lhx]

I ordered and paid for an item. I received a tracking number almost imidiatly but after 18 days the item had not even been dispatched. I complained and posted a poor review 

The seller has sent a number of abusive emails and was clearly attempting to provoke an argument 

He has now said that if I post a positive review he will refund my money .... this is clearly blackmail 

Not wanting to get into a big fight and only wanting to take the easy route I posted a neutral review and bland comment 7 days have passed and no refund. 

What do I do .... do eBay offers a resolution service or do I just write the money off and move on

[siennagoldmgf]

bay has a money back guarantee.... https://resolutioncentre.ebay.co.uk/