Apparently Twitter blocks accounts to make you give them your phone number.

I have no phone number on my Twitter account. Today I was locked out, Twitter said I had to provide a phone number to get a code which would then let me back into my account.

That was all...no rule violation, no claims I did not something wrong, just phone number=code=back in.
Exactly what their e-mail support said to me a minute ago.

Ironically, my landline is dead this weekend b/c flooding after heavy rains.

so I googled and found an interesting page on how Twitter has been doing this for the last couple years, and how to get back in without giving them a number. takes a few days for them to do it, tho.

twitter claims they have a right to send text messages to your phone, once they have the number.

https://twirpz.wordpress.com/2017/09/01/are-twitters-locked-accounts-a-ransom-racket/