Not Getting Salary, Claims Amounts on time.

Dear Sir, I am working with a chennai based IT company having since 10 january 2011 as per my offer letter my salary is 7000 take home plus monthly convence and provident fund. 1. Since january 2011 to till date i am not getting salary on time. Some month on 5th, some month on 15, some month on 8th, some month on 20th. 2. My job is a field job require petrol, mobile and lunch whose amount is payable by company every month but they are not paying the amont with salary. 3. To earn 7000 take home i need to expand 3500 in petrol, mobile food etc and serve the customer of the company. 4. Even when i ask them to pay my final amount and releave me with my PF, They told me to get a PF i need to work for 5 years in the same company. 5. Even few month after i started my own business also and resign but they replied they dont have any problem with my business. They told me to continue the job to get my pf they dont have any issue against my business. They also increase my salary and assure me that i will get my payments on time. 6. Still they are not paying my salary on time also not paying my convence on time and they are deducting my pf but not giving me pf number to get the pf amount balance. Over all they are harrashing me mently and giving too much pain by not paying my salary on time and asking me to close their customer calls with my own convence which later they are not paying properly.