Yatra Air india - Cheating with Customer

I have booked Air Ticket from Varanasi to Mumbai , travel date **-may-****. Total booking amount was Rs. ****. Airlines has refunded full amount but they have plan to refund only Rs. ****.
Below is the more detail about the ticket Price:
Total Ticket cost before discount = Rs. *,***
Discount if paid via PayZapp = Rs. ***.
Total Amount Paid after Discount = Rs. ****.

Yatra is refunding by deducting Rs. *** again from actual amount paid i.e **** - *** - (Some charges from yatra) = ****.

I wanted to know from yatra, if I have paid Rs. **** then why the refund amount is Rs ****.
If you are saying, deducted promotional discount then please remember ticket cast was Rs. *,*** before promotional discount. You should deduct from *,***. Not from Rs. ****.

Let me give you simple example because Yatra people are week in calculation.

Suppose ticket price is Rs ***.
**% promotional discount applied, so customer has paid Rs. **.
Lets consider yatra service charges for booking is Rs *.
So customer paid Rs ** for booking.

Now, Flight cancel due to some reason and airlines refund full amount of Rs. **.

First Q to yatra, what should be refund to customer.

customer has paid Rs **. Then Yatra should refund Rs ** to the customer after deducting service charge, not ** - **% promotional discount - service charge = Rs. **

If you refund Rs. **. It is understood that Rs. * is your service charge but where is Rs. **. Is it lost in space.

Similar case is with my ticket. Where is Rs. ***.

Please resolve it asap other wise I have to take legal action as it case of cheating with customers and I am you have did it with many customers.