State Bank Of India [SBI] — charge dispute "refund not received"

Address:

Amazon World Trade Center - Brigade Gateway, 8th floor, 26/1, Dr. Rajkumar Road, Malleshwaram(W), Bangalore-560055, Karnataka

To,
The chief branch manager
State bank of india
Main branch

Dear sir

A refund of 728 rupees was successfully processed on 21st april 2019 to my account. This amount should have been credited to my sbi account by now, but i have not received the refund till now.

I have called the state bank of india customer service but they told me they don't have any facility to check any details about my refund. No action is being taken.

I have confirmed with amazon and they have successfully processed the refund and the refund reference number of the transaction is 861680.

Kindly solve my problem as soon as possible.