Hi Steve1947,
Welcome back to the Community Forums and thanks for posting.
We'd be happy to add voicemail service onto your account for you from here. I'll pop you over a PM so I can take some further details.
In regards to the issue you have with reaching the REN limit, it's possible that if you have multiple handsets connected, that you may just being going slightly over the REN limit.
Please look out for my PM at the purple envelope.
Thanks,
Beth