What does it say when you try to access it? Are you otherwise able to use your phone? Do you have easy roam enabled?

Easy roam enabled. 

Dial voicemail and local service provider system says: “unreachable number...”

Tried to access my voicemail through local phone, failed 3 times and got Blocked.

Did you try calling your voicemail according to your access number and see if that works instead? 

Can you dial your own number from the Koodo handset, that should also connect you to your voicemail.

What did you do to access through local phone and how did it fail 3 times? 

Also, please elaborate on being blocked. Did you get a message saying you’re blocked?

Typically, dealing your VM from outside Canada should be composed like this : + 1-XXX-Phone number

I got blocked out of voicemail when I entered the password incorrectly for the third time.

I am outside Canada, I want to reactivate my voicemail access and if possible be able to listen to my messages on my phone.

Have you tried reseting your voicemail password?

In the link below, tap the dropdown menu labelled “Forgot your Voicemail password?” and follow the instructions to reset your voicemail password.

https://www.koodomobile.com/en/help/voicemail

If you’re not able to reset your voicemail password, send a PM to Koodo via FB Messenger or a DM via Twitter. 

https://www.facebook.com/Koodo or https://twitter.com/koodo