Is this an error when setting up your account or have you actually changed your name by deed poll?
If you are trying to just transfer one account to a different name, this is not possible without starring a new contract.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion.
This is not Customer Service so we are unable to help with account specific issues.Currently using:
Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)