Once you change your bank details, it can take a few days, 5 or longer for eBay to verify that the genuine owner has made those changes.
You can appreciate, a change of bank details cannot be immediately accepted, it could be a sign the account has been hijacked.
Contact Customer Services, see if they need any verification from you, perhaps the need to send micro deposits to that new account for you to confirm back to eBay, but only eBay can tell you what is needed.
Contact eBay Customer Services it's not easy nowadays to get a live agent , but some have had success using the app, otherwise keep typing in ' I wish to speak to an agent' and this too can work.
Use this link to contact CS, if you can try at 8 a.m. on a weekday morning also more chance there for Dublin to answer.
https://www.ebay.co.uk/help/eua?id=5190
Lines open between 8 a.m. to10 p.m. on weekdays.
9 a.m. to 6 p.m. on weekends.
@equines07