Amazon India — Amazon cancelled my prepaid confirm order for moto turbo

Address:	Pune, Maharashtra, 411067
Website:	WWW.Amazon.in

Hi,

I had placed my order for moto g turbo which was priced 12499 ₹ and after applying promo code it became 4599. As informed by Amazon that it was technical mistake but how their system accept promocode which was entered by us. So basically if we consider this things Amazon will cancel customer orders in future also and come with answer of technical problem.
Everything was OK because promocode accepted by Amazon if it was not true than how system allowed us to apply the same. Why they have generated order number with offer details. Why they deduct amount from account...??
My order number is -
[protected]
I have paid my amount for that mobile and want my deal. This kind of things was not expected from Amazon ("aapni dukan" ).