Wifi no longer working after ISP activation

I bought the AC1200 Wifi Cable Modem Router (Model C6220). When first setting it up, I was able to connect to the wireless and log into it. After contacting my ISP and them activating it, my wireless no longer is being broadcasted and the only way I can connect to it is via an Ethernet cable. When I do connect to it that way, it does have any of the advanced features for wireless as it did before. I was able to do a factory reset, and the wireless and features came back, but it seems as soon as it gets a signal from my ISP it reverts back and the wifi no longer is being broadcasted.