Nope it's not a scam, but as you have returned to selling after a bit of a break have you fully and correctly registered with eBay's Managed Payments? All sellers have to, to be able to list items for sale, and to receive payouts from the sales.
Follow the instructions of the link below, and see if this unlocks your account for selling, otherwise you'll need to contact eBay Customer Services and explain these are used items, where receipts have long ago been thrown away.
You need to provide eBay with details of a bank account and have this account verified. The usual method here, is for eBay to send 2 micro deposits into that nominated bank account for you to receive, and confirm to eBay.
Once this is completed, you will be able to list items for sale, and receive payouts from those sales.
This will show you how to register for eBay's Managed Payments.
https://www.ebay.co.uk/help/help/selling/getting-paid/introducing-managed-payments-ebay?id=4795
If there is an issue with the registration contact eBay Customer Services, who have full access to your account, and can see where the issue lies and explain the steps you now need to take.
Contact them this way.
Scroll to the very bottom of the page on the link below you will be able to access eBay Customer Services through the Contact Us link.
https://www.ebay.co.uk/help/buying/search-tips/advanced-search?id=4049&query=1455&st=GENERAL_SEARCH
Lines open between 8 a.m. and 10p.m. on weekdays, and between 9.am. and 6 p.m. on weekends.
