I recently completed a change of ownership from my mother's name into my name, which has now gone through (I got emails saying my mother is no longer responsible for the account as of yesterday). I have issues trying to log in to my account though, I log in with my email address and it takes me to a 'link my service' page instead of the My Account Dashboard. When I put in my mobile number it says "The service entered is not eligible for My Account registration."
I am also unable to log in to my account on the Optus app, however my mobile usage is shown without being 'registered' to an account.
During the time the account was under the name of your mother, were you able to login to your My Account using your own personal email address as your login?
Normally, we'd need to go in and un-link the service from the old My Account profile and setup a brand-new profile for you.
It's a really simple one, but you will need to contact us to get this organised. Our Social Media team are great with these sorts of issues. I'd send them a message over Facebook or Twitter. They won't be able to respond right away, but if you bear with them; someone will respond back.