Contact eBay Customer Services asap their lines open in around 2 hours, at 8 a.m.
Contact them this way.
Scroll to the very bottom of the page on the link below , and click on Contact Us.
https://www.ebay.co.uk/help/buying/search-tips/advanced-search?id=4049&query=1455&st=GENERAL_SEARCH
Lines open today between 8 a.m. and 10 p.m.
Change passwords on all accounts you own, especially your email account, and contact your bank and Paypal, inform them too, of this breach.
