It is always better to tender notice of resignation and, avoid abrupt termination. You have worked for long with this company and at the end tender some reasonable notice say 15-30 days. If you have to join another company then decide as per time available. Address your notice/resignation to good offices of appointing authority, Head-HR, MD and ask to pay gratuity in FNF.
Since you have drawn salary, company can content that appointment was accepted without appointment order, and certified standing orders shall apply. You may obtain copy of certified standing orders of the company, which are to be circulated to all employees and displayed at the gate. These may be on HR page of the intranet of the company or with concerned personnel of HR, old employee. You can demand these and company is duty bound to supply these to you. If certified standing orders are not applicable model standing orders shall apply.
You may contend that no appointment letter was ever issued and you have not signed on terms and conditions of termination/notice pay etc.
DOJ is specified in salary slip. Hope you have 1st salary slip and salary slip is issued by same company name all these years, and company has not herded all employees at one place and obtained resignation and enrolled employees to new company (like.Bharti Airtel). Employee is to be enrolled for PF from very first month of employment. Obtain PF accumulation reports for all years of employment from employer which if not supplied must be lying with concerned personnel of HR. Employer is duty bound to supply it to employee.
If there is some error in your DOJ noted by you raise the issue in writing under acknowledgment now and get the correction endorsed and updated in all records.
If company is shifting, changing, company is duty bound so must have supplied circular and letter to all employees on shifting/changing, transfer guidelines, benefits, etc and guidelines to all employees who do not want to shift. You may seek separation under this condition.
THE PAYMENT OF GRATUITY (CENTRAL)
RULES, 19721
3. Notice of opening, change or closure of the establishment.-
4. Display of notice.-(1)
7. Application for gratuity.-(1) An employee who is eligible for payment of gratuity under the Act, or any person authorised, in writing, to act on his behalf, shall apply, ordinarily within thirty days from the date the gratuity became payable, in Form 'I' to the employer: