The roaming package is just to get cheaper rates and shouldn't affect you getting service or not. Do you have a spending cap on your line and possibly didn't get the roaming package before going to the US and may have went over your spending cap?
Try tuning off the phone and pull the SIM Card for a minute or so then replace them and try it again.
Also try manually searching for towers by going I to settings - more settings - mobile networks - network operators and let it manually search for towers then when a list of carriers pops up choose one and see if you get reception.
If not try calling Koodo and make sure everything is fine on their end with your billing and roaming add on.