Has your manager given an acknowledgement of your resignation letter to you?
What does your appointment letter/job offer speak about notice period/buying of notice period etc?
The excuse of the company that you have to apply within 30days is just a company procedure and they cannot deny you FNF because of that factor alone.
Did your company speak about notice period or they have accepted your resignation?
In your resignation have you asked for full and final settlement also?
What capacity were your working and in which industry?
Depending on that you can approach the local labour officer for delay or refusal to clear your dues.
One needs to give more information to get clear advice from members.
20th June 2015 From India, Pune