Motorola (Arris) Surfboard modem, very slow over the past3-4 days

I own a motorola surfboard extreme 3.0 modem. I has been working wonderfully over the past 2 years with not a single issue. Now..since the past 3-4 days, I can not get a download of more than 5 Mbps. It used to be 30+. A lot of the time it is less than 1 Mbps. All of my tv/entertainments is done via the internet with streaming. I spoke with a tech support person last night and they mentioned that there was an issue with my modem and a recent update to it. I am no longer able to use any of my services because my internet download speeds are unusable for what I need. I have the 50 mpbs package and for the life of me cannot figure out what is going on. I have restarted both my modem and my router numerous times. I am by far an amateur with this technology, so there must have been something changed on the Cox side that needs to be either reconfigured or redone. Due to the fact that my service is unusable I am looking at other options for service unless I can get this taken care of. If someone has any ideas what might be going on it would be greatly appreciated!