Continues delay in salary

Dear Sir, The query is regarding one of my friend. His case is as follows 1. Company A hired 10 employees and posted them at client side (Govt deptt). 2. They gave only offer letter, NO APPOINTMENT LETTER,NO CONFIRMATION LETTER (Several mail was sent requesting the appointment letter) 3. My friend has worked with client for more than 1 year. 4. The company always paid the salaries after 10th of every month. 5. Last 4 months, salary was paid after 25th of next month. 6. My friend has resigned the compani and joined other company by serving a notice period of 6 days. 7. In the offer letter they didnot mention anything about notice period. They mentioned only that the detailed terms and condition of your appointment will be mentioned in the appointment letter which was never issued to any employees. 8.At the time of resigning 2 months salary was due and annual component was due.(Total 1.5 Lacs) Now the company is not paying the amount what to do? How can he get my hard earned money? thanx in advance