State Bank Of India [SBI] — my account was debited with rs 6700 on behalf of my customer false complaint

Address:

Faridabad, Haryana

I am clothing merchant, one of my customer came at my shop and purchased clothes worth Rs 6700 on 06/11/2019 and a made a payment using is card by entering is pin, bank verified the pin and approved the transaction, after approval from bank i had delivered the product to the customer.
now on[protected] my bank account was debited with Rs 6700, after asking the bank for such debit, bank employee said that customer has raised a complaint that transaction was not done by him.
i would like to inform you that being a person i have made a fair transaction and delivered the product to the customer in good condition and after being approved by the bank.
and now bank has debited Rs 6700 from my account without my consent,
I have submitted transaction slip to the bank in which approval code is also mentioned but still no action has taken place till date.

i would request the bank to please refund my amount as soon as possible.