If this message is really from eBay, you need to contact eBay customer support in your own country.
First check that it isn't a bogus, "phishing" attempt to get you to give away your password. These often try to panic the recipient into replying by claiming that their account is at risk in some way.
If the message came by email and asks you to click on any link in the email, it's bogus. If it's genuine, there will be a copy of it in the messages folder of your My eBay pages.
