Company forcing me to work on weekends without pay, what to do

Company asking to work on weekly off & daily extra after work hours without any compensation. Not given last 3 year annual increament despite having too much workload & projects. Company Give me pramotion mentioning VERY GOOD performance 6 months before but no salary improvement. Now after 3 years company announce salary increment but not given to me saying POOR PERFORMANCE. This is due to denial to work on weekly off without any overtime or any travel allowance or any compensation from me. Also threats for dismis to me. Last year dismis 50 permanant employee saying no work for cost cutting.But recruited approx 70-80 new persons on contract basis.Under name of cost cutting all facilities for employee cut off. But no cut off in management huge expenses. Bonus distributed only management & top persons. Company made HR policy as per Bombay shop & establishment act. But not followin g that act for Leave pocily / Annual increament & Bonus. I have to file suit against company. Pls. guide me.