This actually happened to me - a decade ago or so, Google suddenly did not allow me to access my Google Mail unless I provided them with my phone number for "additional verification and security". I had got a job offer and was desperate to access my mail and so caved-in with a lot of resentment. (Ofcourse, now it is nearly impossible to create a Google account without a phone number, but in those days people considered phone numbers to be private and were leery at services that demanded it for sign-up). And then, later on they suddenly stopped allowing you to reset your passwords using email and security questions unless you provided them even more data for "verification" (which nearly often wasn't enough to allow you to recover the account).