If the email addy is yours try forgot password? Would it be possible that it's a common email addy and there was a typo by others?
https://iforgot.apple.com/password/verify/appleid just in case you was drunk when you set up a AppleID
The same problem I was faced when I activate my iPhone without Apple id and I can't create a new one. So my friend suggests me this blog and link and now I used without any problem. He had also the same issue while ago. I'll give you, I hope it will help you. https://www.iphonesupportnumber.com/blog/how-to-activate-iphone-without-apple-id/