Arris SB8200 Modem - Comcast Won't See Modem

Hello!

I got an Arris SB8200 modem and when I tried to get it provisioned by Comcast they couldn't see it. I know this modem works but for whatever reason, it just couldn't be seen by the system. Looking this issue up on the internet after going back to the old modem I found out that A LOT of people have an issue with this. What can I do? I want faster connection but I'm not going to keep buying modems until they work.