Depending on the reason the seller gave for the cancellation, they may have received a damaging defect on their account. It doesn't take too many for eBay to remove a Private seller from their site, for bad selling. eBay do not like unhappy buyers.
If they used the excuse, ' Buyer Agreed to cancel', or ' Problem with Buyer's Address' contact eBay Customer Services, explain this is not the case and you were disappointed not to receive your paid for item, they will place that defect on the seller's account.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
I recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
If you paid with PayPal that is actually the quickest way to receive back your money, should be a few days only. Paying with a credit card can take 30 days to receive money from refunds.
@eye.d.crisis