Promised salary was not paid for 12 months.

I joined in a private college Bangalore on June 26 TH 2014. i joined as a junior English lecturer(part-time) for PU college but i was the only one handling all the classes. *in the month of November 2014 they made me full time lecturer and my timings also changed from 8:30 -12:50 slot to 8:30-4:30 slot. * my salary when i joined was 25,000/-pm. and the management promised 40,000/- from November but it was not put on papers. i had been constantly reminding about my arrears through mail and phone. *i could not carry on anymore so i sent resignation letter on 8 July 2015. since the portions for students were to be completed they again gave false promises and asked me to be part time lecturer. but the principal did not heed to the fact that AGM gave me part time and he even threatened that my daughter's class( she studies in the same college) would be effected if i dint come early and work .( that is again for full time) now on 24 th November i could not bear up any more so i resigned finally. 1. i have audio recordings of their promises 2. no written records. 3. constant reminding through mails to the management. 4. they gave me designation as Jr. Lecturer but i was the only lecturer handling around 500 students without any help. 5. my in-time and out time records( stating my change of working hours entry) 6. as an employee they promised me a discount of 30,000/- but not sure if they would give that discount. Please help in my issue . i do not know how to proceed . i feel i am exploited completely and harassed. i also fear my daughter's plight at the college. Thanking you in advance for your valuable suggestion.