Apologies for posting in wrong forum.

A bit of an annoying situation, my elderly mother currently has her 'Not verified' local New Zealand landline listed as the Google Phone number.

If I go to verify, change or delete the number I'm met with "There was a problem with your phone number" because Google can't send a text to the landline. Selecting 'More ways to verify' only presents "Get a verification code at landline".

I can't make any changes to her account without getting past this verification method.

Any clues how I can get the landline deleted and replaced with a valid cellphone number?

Thanks in advance.