THE AGENCY REFUSED TO GIVE A COPY OF THE CONTRACT

Good day!!.im a registered nurse currently working as a private duty nurse under an agency.im a member of this agency since april 2013.then they gave a client immediately after they hired me so may 1,2013 i am working with same client until now..but i filed my resignation to agency last july 2013..they hold my resignation until aug 2013 and still continue paying them 15% OF my salary.and another condition that after i resigned to them i can no .longer work for their client where in this client they are refering offered me to resign to them so i can have my full salary without paying them..but the agency said it is not allowed i should not be coming back to that client after i resigned to them.so by sept.i will not work for this client without telling them because im no longer
Part of the agency..they said if i return to work with this client after my resignation to them they will file a case against me they said its in the memorandum of agreement i supposedly signed prior my engagement to them.then i asked for the copy of the MOA so i can make it sure if it is really stated on the agreement but they refused to give a copy..what are my rights about this???and how can i file an official complaint against them??until now they are still accepting applicants that can work for them because each nurse will pay them 270php every day..if am not mistaken they have 240 members as of april 2013..im paying them EVERY DAY 15% of my salary plus 500PHP MONTHLY even if ur not working they call RETAINMENT FEE..and 1200PHP ANNUALLY without official receipt..i am hoping for your response.. thank you so much and morepower!!