New service at my place of work being told only one modem available???

So we are upgrading my place of work to add Comcast Business and dropping our previous provider.  The sales rep is telling my office manager that they only have one modem now.  Two years ago when I signed up I had TONS of issues with SIP ALG, crappy modems and a whole host of other things that plagued me.  Finally I got a modem that works and I am happy (god forbid anything happens to that modem) I got a Netgear and it doesnt block my SIP traffic, hasnt dropped my connection in about a year now etc.

If the only modem available now is the Cisco modem for customers that need static IP's is it plagued with all the same issues with SIP like my prevous modems?  Can it be completely bridged?  Shut off firewalls for Static IP assignment?  Grab that IP directly from the modem?

I am really worried and think I am almost best to take the internet a different direction, what are any of your thoughts on this?  We are specifically moving our internet to a new provider for the purpose of having reliable SIP as our current provider is dreadful!!