Open a case for item not received, one day after the item's last estimated date for delivery.
Go right of the item purchased, and from More Actions select.... I Have Not Received My Item.
If you are not fully refunded within 3 days, you must escalate the case on day 4 or within 30 days from opening the case, and eBay will step in and force the refund.
Do not close the case early for any excuse or promise the seller may give, and do not forget to escalate.
It's worth reading eBay's 30 day MBG, Money back Guarantee policy if you wish to continue buying from eBay. It's written on the right hand side of every listing.
Read about it from this link, too:
https://pages.ebay.co.uk/ebay-money-back-guarantee/
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