You can withdraw the resignation before acceptance.
If you are assigned to projects that does not mean that your resignation can be accepted before expiry of notice period or you can be terminated.
You can send notice of resignation hard copy by Redg. Post.
If employee has decided to retire by resignation then employee can submit FormI (for payment of Gartuity) 30 days before date of retirement.
You can clarify that you have submitted notice of resignation and explained in office too and have sent the same by post.
Good offices are o/o appointing authority,MD,Chairman etc and resignation should be addressed and sent to appointing authority that has signed appointment leter.
If the establishment works for <6days/week then employee should have worked for 190days………..
There are many threads on similar query at following link and many judgments are quoted in the threads:
https://www.lawyersclubindia.com/forum/display.asp?cat_id=9&forum_id=49#.Vfa6_31-jMo
e.g;
https://www.lawyersclubindia.com/forum/Am-i-eligible-for-gratuity-126492.asp#.VfkdTn1-jMo
https://www.lawyersclubindia.com/forum/Clarity-between-gratuity-eligibility-service-5-or-4-8-yrs--28768.asp
If you are unable to handle on your own then you may consult Employee’s union of your trade……………….and there are many unions now/Trade Unions leaders e.g. CITU/INTUC/AITUC/BMS etc and draft your representations in consultation with them and/or elders of the family, able labor Law Consultant/Service Matters Lawyer/Law Firm.