Eligibility for Bonus Under the Payment of Bonus Act, 1965
If any employee whose monthly salary does not exceed Rs. 21,000 works for not less than 30 working days during an accounting year in an establishment to which the Payment of Bonus Act, 1965 is applicable, they are eligible to claim a statutory bonus as per the provisions of section 8 of the Act. This is on par with other employees who are in service on the date of disbursement of the bonus pertaining to that year.
Therefore, it is not necessary that they should be in the employment of the establishment on the date of payment of the bonus. Certainly, you are entitled to a bonus for the AY 2018-19 since you had worked up to March 2019.
Steps to Take in Case of Refusal
In case of refusal on the grounds of your resignation, you can file a claim under section 21 of the Payment of Bonus Act, 1965 before the designated authority or raise a dispute under section 22 of the Industrial Disputes Act, 1947 before the area conciliation officer.