State Bank Of India [SBI] — fin charges regarding the sbi bpcl credit card

Address:

Kamala goswami chawl,beside bldg no 310,Bandra east,, Mumbai City, Maharashtra, 400051

I had paid minimum balance of credit card on 03 Nov for the billing month of October but they had charged me RS:1689/-, but I had paid full amount for the billing next month i.e. Nov on or before 23 Nov then they had again charged me in December month RS:874/-why is it so I didn't understand if customer is paying a minimum balance then why they had charged me.
kindly please do needfull as soon as possible they had charged money around 2663/- for both month.
And I am requesting to cancel this credit card, the entire conversation was regarding SBI BPCL credit card of no: [protected]...