What is/was the expected delivery date? This will be stated in the listing.
If that has gone by a couple of days ago, then open a case for “I bought an item. I haven’t received it yet” in the Resolution Centre.
http://resolutioncentre.ebay.co.uk/
Escalate to eBay after 4/5 business days if you have not received the item or a full refund in the meantime.
You have 30 days past the latest expected delivery date to open a case in eBay.
If you are too late for an eBay case, open a similar case in PayPal (if you paid that way). You can open a case two days after the expected delivery date and escalate it to PayPal on day 2-20 after opening the case. Log on to your PayPal account, find the transaction, and go from there. You have 180 days (about 6 months) to open a PayPal case.
https://www.paypal.com/uk/smarthelp/home
