Internet connection problem

I have two networks in my office 1-all the computers and laptop, 2-all camera and smart things. Then i have 2 ATT modems one for network 1 and other for ntwk 2. but the internet in ntwk 2 is not working as some wire or somethings from ntwk 1 is dominating the ntwk2 and the camera ntwk is getting the ip address of network 1and the internet is not working I have a cisco router connected to modem 2 and all the POE are connected to routers  I have two separate server rack for both network and all wires are labeled.