TylorSkory
I Love YTtalk
Contact your partner manager and explain the situation to them. They are there to help you. Remember though, you already signed a contact, so they are in no way obligated to release you from it, but chances are they aren't going to want to have you on their network if you have copyrighted content on most of your videos that they are making money from (as legally, it could actually get you both in trouble). Or simply ask if you can "unclaim" these videos and make a better effort to use copyright free or creative commons music in the future. Good luck!
Edit: Or are you not actually partnered with a network?