Fired instantly without giving official termination letter

Respected Forum, I am an employee working in a private limited company since last one and half years as a manager, before joining an offer-letter was provided to me, that in the contract if any of the parties terminates or resigns without prior one month's notice, he/she has to compensate one month's salary in lieu there of.Again , in the offer-letter my total salary was written but no deduction was mentioned if I was absent. And every month , they used to deduct from my salary of no reason or whatever, because the accounts people used to manipulate the attendance record.Now, they are asking me to leave without providing official termination letter, which is still pending till date.I am still coming to office. They are saying they will only pay my 13 working days salary, this month.,nothing else, not even compensate which is mentioned that they will give one months prior salary. Kindly advise me what steps should I take against this company now. (n.b.)-Where I am working the office is a rented flat, not for commercial use.Here there are 5 companies running together under the same roof with one employee each for every company. No P.F or other benefits are there. Pl advise me what needs to be done immediately. Thanx, Sanchari C