Standard Chartered Bank Credit Cards are Cheats

I will put it very Briefly –
I am a holder of Standard Charted Bank Credit Card – 5546 2329 0475 0758. I called their Customer Care around Jan’2019, and I complained that certain charge was wrongly levied on me – which I was told by the Customer Care is being reversed, and after the reversal, and “x” amount is payable by me. I paid the “x” amount to them, and thus technically making my outstanding ZERO with them.
To my surprise I received an sms from them after more than a month that I am supposed to pay an immediate outstanding of Rs 950/- to them, and the TOTAL outstanding was Rs 3897/-. HOW ???!!!
AFTER CONFIRMING to me on Call of the reversal in Jan’19, they Unilaterally decided to levy this charge on me – And Then, levied Late Payment + Interest, PLUS, Late Payment + Interest on this amount – Bringing it to Rs. 3897/-
WHAT CHEATS !!
As of now I am Simply cancelling my Card – AFTER paying total Rs. 3897/-…….And CAUTIONING everyone around to be Careful About getting into a Relationship with Standard Chartered Bank