IP Phones/Asterisk not responding after IP Reconfiguration

I had a company come out today and reconfig our internal Network IPs from Public to Private. After this was completed, I checked the Phones and we have no service. I reset the IP Phones (Aastra), they picked up the new IP Addresses, I connected to the Web Interface and changed the IP Address and still no service. This company is not knowledgable in IP/Voip/Asterisk PBX. I have exhausted all possible thoughts on what to do and where changes need to be made, PBX, Firewall, and IP Phones.

Has anyone ran into this problem and found a solution and can provide me with step by step instructions on how to get my IP Phones up and running.

Thank You


No web interfaces are supported here. Asterisk GUI is dead and FreePBX has its own peer support web site.