Netgear NightHawk AC1900 C7000v2

I started a new Blast 200MBS internet account with Comcast yesterday and purchased a Netgear NightHawk AC1900 C7000v2. I installed my new modem/router after my account was created. I was pulling download speeds in excess of 230MBS yesterday. I had to talk to Comcast about my account today, I think the agent said she need to register my modem/router. As I was on the phone with the agent I ran a speed test and my speed dropped to 60-75MBS over and over again. I was livid, there tech support could not explain what happened and pushed me over to Neatgear without any postitive results. I read that Comcast pushes down configuration files to modems and in my case I got the wrong config file.  Now I have to call Comcast again tomorrow and plead my case probably in vain. Anyone else have this issue or advise?