Hello,
it indeed sounds like you have some products registered to another account.
The good news is that the registration won’t prevent you from using the licenses dongles as you know and you can update your licenses as long as you know which ones you have exactly, in order to buy the correct ones.
(you don’t need to log in to MySteinberg to purchase updates, in any case it’s a separate account to the Shop account, as it’s two different companies)
But the account/registration problem can only be resolved by Support - if you are in a directly supported country and can call them, I’d recommend to do so.
EU: https://helpcenter.steinberg.de/hc/en-us/articles/206530864#pop1
USA: https://www.steinberg.net/en/support/usa.html
Kind regards,