I'm not sure how you've got this set up. If you have two separate lines with koodo, each number would come with its own completely separate voicemail service.

Yes, that is true.  However, whenever I change my message on one line it replaces the message on the other line.

Are you sure you’re dialing to each voicemail right?

They both should be independent of each other.

How do you have it setup right now? 2 sims, 2 esims, 1 of each?

And how are you dialing your voicemail? Pressing and holding one, dialing your own number, etc.

Each “line” should have a dedicated voicemail box. It’s possible that your voicemail access shortcut *ie holding “1” on the dialpad, only dials one of the lines.

To ensure you are accessing the voicemail of each line separately, use a landline to call into one of the voicemail access numbers ie 778-580-4001. Enter your phone number, #, then PIN, #, and then you can modify the settings of each number independently.