Kya Dividend Jitna Kaha Gaya Utna Mila Nahi?

First of all, To be eligible for dividends, you need to be holding the stock in your demat account on the record date of the dividend issue. You should have bought the stock at least one day before the ex-date so that the stocks are delivered in your demat account by the record date.

Record Date: The record date is when the company checks its records to identify the eligible shareholders for a corporate action. Shareholders holding the shares in their demat accounts on the record date are eligible for corporate actions such as entitlement of rights shares, bonus shares, stock splits, dividends, etc.

Ex date: The date on which a stock starts trading without the benefit of corporate action, i.e., ex-benefit, is known as the ex-date. So ex-date or the date when stock trades without corporate action is one day before the record date.

Ex Dates & Record Date for NSE and BSE stocks can checked online.

Now that this is covered yet you have not received Dividend as much as was given to others then you need to understand that:
Dividends above ₹5000 are eligible for 10% deduction.
TDS of 20% will be applicable If the registrar (RTA) of the company doesn't have the PAN details of the investor in its records.
TDS of 20% will be applicable for all non-resident shareholders.

In case none of these apply with you then you should immediately take up the issue with NSE Investors Grievance Cell.