HDFC Bank — DC INTL POS TXN MARKUP deduction from my account

Dear HDFC Team,
I am currently residing in Kerala. I have used an HDFC Debit card for exam registration purposes, however recently I came to know that there is a. DC INTL POS TXN MARKUP deduction from my account. There was no prior intimation from the bank, nor an email.
Without informing how could you proceed with the deduction???
Was there any agreement or any contract signed by me???
Why don't the banks intimate the customers while opening the account, especially with international transactions????

Would request you to please intimate or send messages or WhatsApp to all those customers who are using your card internationally.
Till date you have deducted INR.1043.60 from my account.

No information on how much you are charging??
Where are the RBI guidelines mentioned in regard to the extra charges????

Waiting for your reply and also the refund from the bank with immediate effect.

Email - [protected]@gmail.com

Regards
Geeno George