HomeTown — Misleading customer service...

I booked a ticket from Bhubaneswar to Chicago and there was a promo code that u will get 25% ecash back.. But as I was booking I did Not see anywhere that at one time you can only use 5% from the ecash for the next booking and the guy from the customer care also after asking 3-4 times that there is no terms and conditions for using .. He said no except for that u have to use it within 90 days... I got like around 20 k in ecash ... So how will I use.. Am I gonna book tickets n tickets for the whole year to use those ecash... Really ridiculous... I was always reluctant to book from yatra.. But seeing that deal I booked but now I feel like I have been cheated... If I would have booked with my international credit card I would have got 300$ in return for booking a 1000$ ticket... This my worst experience with Yatra.. Never ever am gonna use their site... Now I don't know how to use their ecash when n where..