You need to first notify your bank of this breach.
Contact eBay Customer Services to block your account, if it's this one they are using, until you can sort matters out with your bank.
To Contact Customer Services it's a Live Chat, or you can select to speak and request a Call Back. Click on this link:
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
On weekdays lines open between 8 a.m. and 10 p.m.
On weekends they open between 9 a.m. and 6 p.m.