Amazon India — Cancelled my order[protected]) without any reason

Address:	Bangalore Urban, Karnataka, 110006
Website:	www.amazon.in

I had placed an order (Moto G Turbo Mobile phone )
my order id[protected] Placed on Sunday, March 27, 2016.
but at the end of day i got email that they cancelled my order and generated refund for the same by saying this was an Error of price.
Actually i ordered this phone worth 12499/- at 4999/- by using coupon code - GYJQJ3YW and it provided me discount worth 7500/-.
Over thousands of customer had placed order for the same but amazon cancelled all the orders.
Even this is not the first time Amazon has done this.
please check into this matter, we earn money so hardly and websites like this exploit us and block our money.
they generate huge amount by doing this and make their work and at day end send us a mail regarding cancellation of order.
Really its a shamefull activity done by the trusted website AMAZON.
I HOPE YOU WILL INVESTIGATE INTO THIS MATTER AND MAKE SURE THAT EVERY CUSTOMER WILL GET THEIR ORDER DELIVERED AND IN FUTURE EACH AND EVERY WEBSITE THINK TWICE BEFORE DOING THE SAME.