Anything can be said after going thorough your appointment letter as oral communication with your employer/agents does not carry much weight.
Check with employer what reason for delay, as it is better to settle matter between you and employer with engaging third front.
If employer is deliberately delaying your FNF then send legal notice to your employer.
In case legal notice does not sever you purpose then complain to Labour Commissioner. Labour Commissioner will forward your matter to Labour court in case your employer does not settle matter at Labour Commissioner.
Thanks and Regards
Deepak Joshi & Associates