No internet connection

Hi I'm a new subscriber to cox internet. I live on a military base and cox said their tech cant get on base to help. I have talked to the techs on the phone but they were unable to help. I bought 2 brand new modem/routers just in case one was faulty and even tried connecting directly to the cable in the box outside the house. (It doesnt have a lock) the modem shows online but all devices say no internet connection. I telework so I need internet and cox is the only provider here over 3Mbps. Help!