Sbi Cards & Payments Service Private Limited - Money laundering by the company

I have been charged two times the conversion fees on the name of markup fees. One is the time when sent an international payment and the other on the amount in the card statement.
*) When I sent an International payment the currency conversion charges take place and I had to pay extra * to * % on the total amount I sent.

*) Now when the amount which I sent is shown on my card an extra *.*% charge is applied on the same transaction.

In the first case suppose I sent * dollar internationally and the current conversion rate is ** INR to * dollar but they charge me ** INR in the name of currency conversion which is done with the card.
Secondly now on that ** INR extra *.*% is what they charge more on the name of markup fees.
So they just robbed and took my money even though I had been their client for almost * years. I had called customer service a lot of time and even raised a dispute with them but no response. So I stopped paying the bill and they keep on calling to pay the bill by still no resolution of my complaint and on a credit card worth limit **,*** that had created a bill of **,*** saying I am not paying the bill even though they had delinquent or stopped services on my card but still continually charging me on the name of late fee.
I hope you take this matter seriously and resolve my complaint and send a notice to SBI card immediately which is a privately owned entity misusing the name of a renowned SBI bank.