That was exactly what I received 2 days ago as well!..
''We're closing your Opera account unless you sign in' .. blah-blah-blah .. 'please sign in' .. or .. 'we’ll take this as a sign that you’d like us to delete your account' .. blah-blah-blah .. '
As was suggested in that email (that was, by the way, emailed-by 'mail71.atl111.rsgsv.net' in my case), I reset my password and signed in immediately, and what, You think, I have as a result - despite the fact, that my account was registered more than 4 years ago, the system is wrongly 'saying' now that it was only created just 2 days ago!..
Well, my dear Opera, You know, from around that moment(s), when You shut down Your good-old My Opera Link and My Opera Mail (and MyOpera in general) and after all of this presently, I'm disappointed in You and seems don't understand anymore, how even can I trust You (and in You)!.. Unfortunately...