Finance Charge

I have been charged a finance fee for the past 6 months on my credit card. My minimum payment is R380pm and finance charges are +-R280. Which means I only end up paying R100 towards my debt. Why am I being charged this fee when the card does not have any transactions ?? What is a finance charge ? I pay a service fee, credit card facility service and maintenance fee but still have to pay a ridiculous finance fee ? Make it make sense.