The only way to be sure, is to contact eBay Customer Services, and ask if they sent it.
eBay will always address messages to you, by your real name, and never your username ID, sometimes bad spelling / grammar can be a giveaway, but most look very , very real, don't click on any links.
This is the easiest and quickest 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 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
I recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@adepar