We recommend agitating each bottle and/or moving to a warmer temperature (70+ °F). If you added the sugar it will carbonate. Some styles will take longer to carbonate than others, and temperature can play a big role in carbonating a beer as well.
It is not unusual for a beer to take 2-3 weeks to carbonate. Just open a beer each week until the carbonation level desired is achieved. Then place the beer in a cool location (below 55 °F) to prevent over carbonation.