Labour law violation approximately 50 staff - no appoint letter, salary description, PF, ESI to the staff?

Dear sir, My self from vadakara, kozhikde. I am working in a service centre of royal XXX. approximately 50 numbers of staff are working in this service centre. But no body have PF and only 10 staff having ESI.compony never give a salary description or appointment letter.i have completed 3 years still working there.there is no HR manger. There is no HR policy.
May know.. is the company no need to provide appoint letter, salary description, PF, ESI to the staff??
What i can do against the company for this exploitation of 3 years from joining .

Every employer is bound to comply with the provisions of all the labor laws applicable to his establishment. If he wantonly fails to do so, it implies that he has some hidden agenda to deprive his employees of their long term employment rights and benefits for obvious reasons. Better make a detailed complaint to the State Labor Commissioner and the Regional P.F.Commissioner. In order to avoid any retaliatory action by the employer, claim anonymity or let the complaint be made by any popular Trade Union Federation.

For ESI Act non compliance you can approach ESIC office of your area.
R N KHOLA