Microsoft: Official Support Thread

I have chatted with a live agent already but I'm hoping there's a chance there's an alternative. I am trying to help my grandfather get into his account which he has lost the password to. Previously when he's lost a password, we reset it using the option to receive a call with a security code. However now only text is available and we can't receive it because the phone number is a landline and the telephone provider doesn't support text to landline anymore. The live agent tried to help, but all she could do was send us to the Account Recovery Form which I've tried and been rejected multiple times. Is there any way at all to receive the security code by call? It is the only security function we are able to access successfully.

/r/microsoft Thread