Once plugged you may need the services of a plumber Or youy can try an Auger.
Then after this is cleared you can look in the tank and double check the flushing action.
With the new 1.6GPF there is not that much room for error on how long the flapper/tank bulb stays up.
You want to get the most water into the bowl as possible.
Using a plunger may cause more problems as it can wedge a foreign object even tighter.
Unfortuntly not all brands are equil and are not the same Quality as Crane toilets are.
The $59.00 Crane I never had any call backs even after installing over 1,500 of them.
Hopefully the auger and adjusting the water level and flapper should work.