Unable to access irrigation controller remotely with COX as ISP

I recently installed a Rainbird "smart" controller for my irrigation system.  I can communicate through the app with the controller within the confines of my home wi-fi network, but am unable to do so through a cellular connection when I'm away from home.  This is one of the main reasons I purchased the controller--to be able to change the settings when I'm away for the summer.  In talking with the Rainbird reps, they asked me to contact Cox (my ISP) and tell them I need them to open Port 80 to all access to the MAC address.  When I talked to Cox about it they said that Cox internet is blocked for Port 80 and they could not help me.  They indicated that I'd have to switch to a different ISP if I wanted that access.  I assume it's some kind of security issue, but I'd think that given the size of COX and Rainbird, this would be a known problem with some sort of resolution possible??  Anyone have a similar issue??