I am only getting one channel out of my cartridge‚ is there a way to fix this?

Firstly, it may be worth investigating if there is any buildup on the contacts on the cartridge or inside of the tonearm.  A common eraser on top of a pencil is usually able to remove light oxidation from the terminals.  It is also possible to use rubbing alcohol to clean the contacts inside of the tonearm, but never lick the contacts on the back of the cartridge, as it will corrode both the contacts of the cartridge and the tonearm.  Secondly, there is a seating procedure which usually remedies this issue:

1. Place the cartridge into the tonearm and apply firm, steady pressure.
2. Turn the locking nut in the opposite direction, as if you were loosening the cartridge to remove it.  
3. Continue to turn the locking nut until you feel the cartridge being forced out of the tonearm.  After the cartridge is nearly forced out of the tonearm, continuing to turn the locking nut will result in the cartridge forcefully popping back into the tonearm with a clicking sound.
4. At this moment, tighten the locking nut in the appropriate direction, and the cartridge should be seated optimally.