Amazon India — my refund has not been given to my bank account.

Address:

Sambalpur, Odisha, 768006

I ordered mi a2 and due to some problems i cancelled the order. The phone has been returned to the seller. But the money has not been refunded to my bank account after one month has passed.
I have tried to call amazon costumers care but they aren't solving the matter.

Order date -13-oct-2018

Order[protected]

Order total - 13, 499.00