Hi Matt,
Glad they got you sorted out.
You can get still get text messages, they need to go via a SMS module texecom do (i think its called a COM-GSM). This can be online the same time as the COM-IP. It just uses a different com port on the alarm system.
We have an O2 pay as you go sim fitted at our showroom for this exact reason, so that if the internet connection went down or it was maliciously cut we get notifications.
The Module isn't that cheap though so i'd only recommend it if you really need a back up solution.