Did you open a return through Ebay?
If so, go to the open case and check that the tracking shows the seller has the item back.
The seller has 48 hours to refund you or you can ask Ebay to step in through the case.
All refunds are made through Ebay managed payments so, if a refund has been sent, you would have an email from Ebay (not the seller) confirming a refund has been sent.
Refunds to credit cards can take several weeks but most refunds are quite fast, Ebay say 3-5 days.
Check your case here:
https://www.ebay.co.uk/help/buying/resolving-issues-sellers/check-status-request?id=4667&st=3&pos=1&...
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)