finance charges not explained

I took a credit card with nedbank in 2019, of late i recently saw a finance charge on my statements which i was never advised about when i took the credit card. I spoke to noleen who was insisting that there is nothing hat can be done, she put me through to complaints were i was transferred to 4 different people and place on hold until i decided to hangup. this is the second time i have taken finance with nedbank and the experience has been awful....