Kotak Mahindra Bank — unusual activity on my account

Address:

Hyderabad, Andhra Pradesh, 500081

Hi,

I did a transaction of 41000 in a hospital on my debit card on 19th of oct.
I don't know why but they (41000) got credited back to my account on 1st of nov, and again debited from my account on 27th of nov.

I don't know what is happening with my account. Please help over this as kotak customer care doesn't give me proper explanation on this and they are telling me to contact the merchant or visa for those transactions on my account.
How can i contact them when i paid amount using my kotak debit card.
Lost belief over the bank to keep the money in my saving account because of these kind o[censored]nwanted transactions.

This lured me to spend the money when it credited back to my account as i thought the hospital refunded me the money because of the failure of the treatment.

I want a strict action against this bank for luring the customers with these unwanted transactions and later asked them to pay the money and everything happens without any intimations.

Please help over this.