You need to contact eBay Customer Services, you may have been trying to contact them when their lines were closed. They opened today at 9 a.m. contact them now, as there's more chance of Dublin answering.
This is the easiest and quicket 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.
As said, I recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
Change passwords on all accounts you own, especially your email account, and keep a close eye on all accounts for the following weeks, for any untoard transactions.
@ando6062