Eligible For maternity leave salary? Got an appointment on probation letter, after that management didn't provide any letter

I worked in one institution from September 2017, at that time I got an appointment on probation letter, after that management didn't provide any letter to me. I took my maternity leave from September 2019 to March'20. Now they telling that I am not eligible for maternity leave. Kindly advice.

Dear friend,
When you raise a question pertaining to a certain statutory eligibility of yours, it is very important that you should provide all the relevant particulars like the type of the establishment where you work, the total no of employees as on date and the maximum no if any in the past, the position of your employment etc. Only then, others can give you an appropriate answer.