Does it give you the option to add another number?
What I would so is close the page, add a new number to your account give it 24 hours as try again, I change a number in between doing it before and got limited.
In my experience if even if you had access to the number it wont work, you have to call in to them. I had this issue on a legit account even and the guy said if their databases don't show your exact name match for that number (your name on the bill/registered for that specific number and lots of cell companies don't even show up) it wont try to text you and you'll have to call in. Its a measure to try to confirm your identity even above and beyond name/SSN match.