This is more of a whinge than anything.
So I have had a business account for a couple of mobiles for a dozen ++ years and I tried to log in to change plans as it was well past contract, with better plans out there, anyway I also have another account for my kids phones as well 7 or 8 years or so.
When I tried to log in on numerous occasions I could only access my kids account - not helpful.
As I haven’t logged in since last contract renewal I did password resets over & OVER &.... (You get the idea) only to get access to my kids account. This was done over a couple of weeks (I lost interest fairly quickly)
So I finally made the call, which was answered by a real person VERY quickly- well done on that one OPTUS (after the self-serve bit at least)
The answer to my question of WHY? Was that I could not have "2 accounts linked to 1 email address” -- Really
"That was done for security reasons a year & a half ago"-- "Really, even though that’s how it was set up & both invoices STILL get sent to the 1 email address" ARGH!!
The only way to get online access is to set up a new email or I have to call in, mmmm.
If you've still reading, well done!
A couple of points & more whinge
You could put all the services on the one account number to make your life that little bit easier, along with data sharing bonuses.
As as these changes were quite some time ago, it’s possible you missed the notification especially if your email provider thought it was spam.