Have the avaya 5400 series phone (5410) and just looking to get my hands on the operating manual / user instructions. can you help.

Do you have voicemail pro or embedded voicemail? Do you have the right document?

It is probably in Do NOt Disturb.
If you press the speaker button, you will hear a broken dial tone IF the phone is either in Do not disturb or forwarded somewhere.

*09 turns DND off
*00 turns all forwarding off

If you dont know, you wont do any good by logging into manager, as you wont know where to go in programming.

Call in someone who knows what to do, as you could do detrimental damage to the system by not knowing what you are doing.

You will need to log into Manager to reset the password.

*00 will cancel forwarding

DO you have IP Office manager?

Press the voicemail button and follow the prompts. You will need to know what the password is. When prompted for the password, try just pressing #

What voicemail do you have?

Exactly. You need an admin rights to log into Manager and remove by hand what you don't need. Find more in the user manual

Try to delete all the messages then try adding a voice mail dialing from another extension then you will recieve the messages.