2010 Volkswagen Jetta A/C works intermently

Symptom indicates an electrical issue rather than with the freon.

It could be the blower motor or its circuit and would require some digging to find out.

When problem occurs, test for power supply to the fan motor. Bang the blower motor housing with your hands to test if the blower starts working again.

Compressor shutting off can be due to a faulty compressor clutch, A/C control module, pressure switch.

Is this an autonmatic or manual HVAC system?

When the a/c doesn't work you can do a few things to test it.

Best inspection would be to remove the 2 pin connector on the a/c compressor and measure voltage and ground across the 2 pins. There should be around battery voltage.
Next option would be to check to see if the fans are coming on. BOTH fans should be on, if the vehicle is warmed up and the a/c is activated.
Last option would be to look at the compressor with the a/c activated and see if the nut/bolt in the center of the pulley is spinning with the pulley or if it's not moving.