Remote Access to server denied

After switching service providers to Comcast and modifying all IP address to allow off cite remote access to my server no longer can we connect through the Cisco modem via Remote Administrator. This access has been flwaless for over 8 years and now we have no access at all. 

All settings have been checked mutliple times including by Comcast Tech support. We are told Comcast can do no more than has already been done.

Surely there is an answer to why we cannot connect.

Any accurate input or response would be appreciated. The Pass Through function is on, all Firewall settings are off.