Update primary account holder information from Mother in law's information back to my own name and information

Long story short- Mother in law had Cox service at a previous residence address with an email address she used for years and years.

She moved in with us and wanted to cancel her service at her previous residence but maintain her email account and its contents.

She was told that to be able to associate the email address with a different Cox account she would have to not have active service at the former residence address.

She cancels service at the old address and is told that her email address has been deleted.

After talking with support and escalations etc...end result is- I am no longer the primary account holder of the Cox account that is serviced at my home address where my Mother in law moved into. (Her email address and contents were able to be kept alive even after the cancellation of her service at the previous address)

I have to log in with her credentials to be able to pay the monthly bill for internet, etc.

I don't use the cox email that is associated with my secondary user on the Cox account so I don't care if it gets wiped out, but we want to maintain her email address and its contents.

Suggestions?

How do I go about updating this information so that I am listed as the primary account holder again.