Same thing with my Skype account. I have it logged in on both my phone and my laptop. One day it decides to automatically log me out on both and when I try to log in it insists on requiring sending a code to a phone number that I no longer have access to. So just like that I lost access to my long time Skype account even though I know the password, even though there's no 2FA setup, even though I'm trying to log in on 2 devices that I've logged in previously, from the same IP address. All support requests went nowhere.

I wonder how many people lost their account like me because of these overzealous security measures.