How to disable Bridge Mode

So long story short , i was tinkering with a old model of an arris router from my local isp , it was showing some slow speeds between 1 to2 mb and the owner is paying for 50mb 

So i saw something about natted mode or  bridged mode somewhere in the management page and clicked Briged and it rebooted right away without it asking for a save 

Now its back up and only one device can be connected at a time , the speed is better but all the other devices on the network are without internet

1st obvious solution is to connect to the modem manually but i don’t have access to that, its locked in a room Somewhere 

So my question is , is there any other way to access it wirelessly, it doesn’t go by the 192.168.xxx anymore it legit has random ips now  , and the gateways for those don’t work 

Thanks in advance for any help