EDIT - I have just read some other threads and it looks like I will need to reverse the "disable" in order to get monitoring working properly. Making sense now. Read on if you need details.
I have had system unmonitored since August 2014. Recently, I decided to get a monitoring plan.
Set it up and tried the test mode per instructions. No joy. Called customer service. I had a TMobile card and they sent a Verizon card.
Installed it and had to go through customer service again. Still no connection to SS. They shipped another Verizon card.