---- In a given situation employee can invoke the Industrial Employment standing orders Act, Payment of Wages Act, SE Act, and ID Act as per explanation of employee under these Enactments or approach civil court.
Companies burn extra energy to convince employee that he/she is not a workman as many of the enactments favor employee and limit the choice to employer. However designation alone does not decide employee is a workman or not.
As per Industrial Employment (Standing Orders) Act, 1946 employer should pay all wages and issue certificate on last day in office.
----If employee has tendered notice of resignation say of one month the date of retirement is known to employer and employer should disburse the gratuity on date of retirement on its own or the employee may submit form I to employer under acknowledgment. If the employer/HR/Line management is not good copy of Form I may also be submitted to Controlling Authority which may be ALC, under acknowledgment