I have a feeling that someone else used the same ID name, maybe, for example instead of
johnsmith@hotmail.com, they accidentally created
johnsmith@yahoo.com (which was your email), realised they made a mistake, left that alone and forgotten, and created another ID with correct email. But the initial ID is still on the servers unused.. I recommend calling Apple ID support and prove them it's your email and that you want to get it straightened out with correct password and security questions. (just tell them you forgot all that info - they'll probably email a confirmation to make sure its yours and then you can have them reset it all - probably). Good luck