It isn’t something the home user can fix. The firmware is part of the ISP’s provisioning when they setup it up. Its not something the end user or arris can push. 

My ISP didn't set it up it's my own modem I call them and they say that the firmware updates by itself but i can't seem to find the update anywhere or i don't know how to push it thru 

Usually Arris develops the software and firmware update and makes it available to service providers.  The service providers qualify, test, and distribute the software update to devices on their network.  CommScope has limited control or visibility on distribution by the service providers.