Company asking for three months salary and training costs

I was appointed as teacher in an IB school run by a Pvt Limited company . Service engagement was for three years with notice period of three months. They took security deposit by cutting 5% on every month salary. One fine day , I was asked to report to a junior class which I refused as my appointment was not for that group . Next day, the director/vice president/principal (same person), asked me to resign and leave the campus in the mid of the day. Which I refused as she was not issuing me termination letter. Then they forced me with the help of security personnel to leave the campus. I did not do any sort of hauling or nuisance . I complained it to police station and subsequently Next day at around 5 pm , I wrote a mail to another director giving all the accounts and shown my concern about insecurity in the campus. There was no reply from them and subsequently , I sent an reminder. But nothing received from their side. After three months , I received a registered letter from HRD (without date and without any one 's name), they are claiming three months salary and training cost (I was not told about the cost of training at the time of training ); they put various blame on me saying that I was shouting and creating problems in the premises. I some one suggest me the remedial actions and consequence.