Amazon - Refund not received

To,
Who so it may concern.
Dear Sir/Madam,
I ordered a product, Zotac GeForce GT **** *GB GDDR* Graphics Card with GeForce Experience **-bit HDMI/DVI Low Profile ****MHz Clock Speed * Years Warranty (* Years Warranty), order no: - ***-*******-*******, on **rd March, ****. It stopped working so, I requested for a replacement on **st March, **** and was delivered to me on *th April, **** but this time the product was defective, so at last I thought of returning it and get my money back. I returned it on *th April, ****, the pickup boy came the next day, i.e., *th April, **** and said that the serial number was not matching, then I contacted customer service and they said we will update the details and filed my pickup date on *th April, ****. The pickup boy checked the product and matched the serial number and said OK and if anything happened after he took it that's not my fault, I just need my money back and remind you that Rs. **** is not a small amount. The customer service said that they are filing an investigation and replied me with the message quoted below.
“Our team had checked the item returned by you. Based on the results of the checks conducted, we will not be able to provide you a refund/replacement for this item as we have received an incorrect item.
Based up on the update we we're unable to issue a refund or a replacement for the order.
I hope you understand my limitations here, based upon investigation team update I can't able to take any action on this order. “
Lastly, it is not problem if anything happened in the warehouse or anywhere else, I am not concerned with that. I just want my refund of the product.
I am also attaching files in zip format to support my query and please have an eye on it.
Thanking you,
Pratik Anand.