Changing names on accounts (contracts) has always been a difficult issue (except in the case of bereavements). I cannot tell you if this can or cannot be done, but given that Plusnet Mobile is in its swan-song months, you might find it easier to get a new service with another provider (in your own name) and then port the Plusnet number to your new account.
One wonders how the business manages situations where a parent has held an account / number in the name of a child ... and at age that person wants to take control of their own affairs / phone number?
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
