I have a customer who is having trouble with their voicemail (ivp8) in their CTX 100. Alot of the telephones Voicemail keys are not working all of sudden (just ring forever) and when they transfer callers to a mailbox the call frequently is recalled back to them. Now if you dial Intercom + 500 (VM pilot number) you always get into the system without any hassle.

Do I just have to reprogram those buttons for vm access or do you recommend something else?

First thing to look at, is to see what is each extension for each port of the voicemail. Then call each port to make sure that they each answer. I've seen ports stop working on older IVP8s before.