Credit card interest rates are right ridiculous

I took out a credit card with standard bank on last year December. I’ve been paying the monthly installment required every month. But my balance or outstanding balance doesn’t change. I’ve been paying for this account since February this year and it looks like am not doing anything all the money that am paying it’s going to the finance charges and some charges that doesn’t make sense. Am not even using the account for withdrawal or online shopping but am being charged for that on a monthly basis. It looks like I won’t finish paying off this account. I want to know why are my interest so high ? Why am I being charged this much and I was not informed about this when I took it out.