Elanic — deducting of discount without information after the transaction is complete

Address:	600010
Website:	Its a mobile App called Elanic

The app had offered a diwali discount on the items that we are selling on the elanic mobile app. They show you the charges that they will be deducting from you for courier and their fee (Elanic fee). So obviously it is understood that all amount to be charged for that transaction will be deducted and charged in that elanic fee component.

After everything is over and the payment is also transferred to my account they mention the diwali discount after a week and charge me again for the same sold transaction. I am not even informed and it shows negative balance in my account.

In the conversation on chat their support person has admitted that its their mistake and that they need to refund.

But now neither are they responding nor resolving the issue.