New device on my apple id

So I got a notification that a new iPad was using my apple id and phone number, but you can't do anything about it since the notification just says "if this is you click ok". Well it's not me so why is "ok" the only option to click? The alleged "new iPad" that's using my id and phone number isn't listed in the list of devices either. I know a lot of people has had this problem but no one has been able to give an answer as to what's happening so I'll add another question on here in hopes that apple will take their thumb out of their *** and actually help their customers.