[jaycee]

This router thing is BS - the tech support guys access the modem from the CATV side of the modem. There is nothing a router can do (connected on the other side of the modem, as the modem is a bridge device) to interfere here.

It is true that a misconfigured router can stop you getting your service, but it won't interfere with Tech Support attempting to access your modem. I cringe every time I read someones post who says "TS told me my router stops them fixing the problem" as it's obviously a fob off