Not sure why you cannot buy but for selling you have returned after a long break have you fully and correctly registered with eBay's Managed Payments?
You may be prevented from listing an item, because you have not fully or correctly registered with eBay's Managed Payments.
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.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open between 8 a.m. to 10 p.m. on weekdays.
9 a.m. to 6 p.m. on weekends.
I recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
@vivahookystreet1
