You haven't provided much info to go on so I'll offer some general advice:
1. Track the package here to see what it shows: parcelsapp.com
2. If the estimated delivery date has passed and the carrier has not attempted to delivery your package, file a non-receipt claim. Instructions if your purchase was made on the .com site: https://www.ebay.com/help/buying/returns-refunds/get-help-item-hasnt-arrived?id=4042
If your purchase was on the .co.uk site then you should find that same help page over on the UK site and can post any additional questions on community.ebay.co.uk
