Not paying salaries

Hello, this is Dr vasanthi, working as junior resident in one of the private institution in chennai since feb 2015, the institution have credited my salary of may month on my account, and taken back the salary the very next day. Then immediately i spoke to ceo regarding this, he said he will sort out the issue at the earliest. Till now i didnt get my pay of month may. I took the issue to the notice of ceo and financial office many times, and official requistion letters had been submitted, but nothing helped me out. Apart from this, they is delayed payment of salaries every month.. Still we didnt get our sep month salary. Aug 2015 salary got credited on 28th of sep 2015. Not only me many of my collegues are suffering from this issue. Few of my collegues who got releived 4 month back, didnot get their pay yet for their last working month.. Though our collegues have given the 30 days prior notice, they are doing this to us. This is what the reason i coudn't even resign.. If i resign i cant get my may , sep and oct pay.. Please guide me and help me out to how to get my pay???