Non payment of actual salary & non payment of salary in time

Dear Sir, My concern : I was approached by the present company I am working with and am employed in senior management position for the past two years with a manufacturing and contracting company based out of gurgaon and registered office in delhi. a) The company has been delaying the salary of all senior employees ( salary above 30,000 p.m) by more than 3 months. This has been going on for one and half years. For mid level employees ( salary 15000 to 30000) the delay is 2 months. Only the workers with salary below 15000 p.m are being paid in time. b) The company has not been paying me the revised salary as per offer letter and appointment letter. My salary was supposed to be revised after 6 months of probation as per the offer letter and appointment letter. It is now more than 1.5 years since completion of my probation but they have revised the salary. They have not yet given me the confirmation letter which was supposed to be issued post completion of probation. c) They have not yet deposited the EPF of employees for 15-16. This has been pointed out to the management repeatedly but there is no action nor any reply. The only reason employees are continuing is : 1. Some employees have dual sources of income ( Though this is against the HR policy set by the company) 2. The employees are such limited skills that they will not get a job in a professionally managed ethical organization 3. For want of another job. I would like to know how I can recover my rightful dues. Thanks!!