Two Step Verification

Good Afternoon,

So around two days ago I got the new Ipad air and I had added my cloud there but for some reason I'm not able to get the verification code. When I try to update a app it says Apple ID Verification then when I click settings and sign in it says Locked and so when I got to unlock it, it shows me a very old phone number from a long time ago. I tried my hardest to find this number but can't. I did contact apple support and a lady was nice enough to try and help me but sadly it never worked. I updated my Ipad and everything yet I can't seem to get rid of the unlock. May someone please try to help for the past two hours I have been removing and adding my current number but it won't change at all.