Well here's suggestion:
1. Start sending out reminder mails with second and third being escalation mails;
2. If 3-4 mails are still not fetching any response, loop in top management whose ID will surely be with you or simply find that out and mail them;
3. If nothing is happening still, consult practising lawyer on how to take the case with Labour commissioner.
13th July 2013 From India, Gurgaon