Tech support installs Static IP, internet is down. Tech switches back to normal, internet is up.

Ok. Business class user with a SMC gateway. Airport plugged into gateway. 6 workstations plugged into airport. Everything works great. Great service. 

Our software people need a static ip so they can access our server i guess. I call comcast and buy a static ip. The tech then installs static ip and says give it a few minutes to reset then send the static ip address to our software poeple. 

Internet no longer works. Not through the airport as before and not by plugging laptop directly into back of SMC gateway. I call back (40mins later) and by shear luck get the same tech that installed the static ip. He tries everything to figure it out. He can see the internet through the gateway, he can see my airport and laptop plugged into SMC gateway. Everything on his end is perfect but i can't see internet. 

We decided to just revert back to original settings before the switch to static ip and almost instantly i can access the internet like normal. 

My question is, is there something I must do on my end after comcast gives me a static ip? Am I to change settings in my laptop or airport after the switch to a static ip? All my hardware is stock settings from the apple store. unboxed Airport and plugged in computers and such. No special network settings on my end. And everything is working great now that he "turned off" the static ip purchase. 

Is it likely that the static ip install was not done correctly?