I was not receiving SMS messages for the rules I setup. This is how I fixed the problem.
Comcast's new home security website appears to be broken so use the old site
From the new site goto the Overview section and click return to previous version. On the old site goto the Rules section and click the pencil icon to edit your rule. Scroll down to step 4 "How Often" and select "Any Time" and save your rule. My original value was set to 12AM so obviously the rule would never fire under normal use. After I made this change text messages started working for me -- maybe it will work for you too.