This happened to me as well when I recently tried to make an account with an email address and no phone number. It was frozen almost immediately after creation,

This happened to me as well when I recently tried to make an account with an email address and no phone number. It was frozen almost immediately after creation, and when I requested it be unfrozen, twitter sent a message to my main email (NOT the one I signed up with!!) and required me to respond and say I had access in order to get the account back up. Made me very uncomfortable and virtually destroyed any desire I had to use their service.