I have used stackkart.com many times and personally I know many names in the company because I used to order over the phone basically. Trust me, they are very nice people and you can definitely give one chance and use their services.
I got maximum discount on the Arihant Publisher’s Books upto 40% and on some other titles like revolution 2020, I too had a love story has also great discount.
One thing I noticed is that they have good Hindi books collection as per other websites.