Unhappy Client

I'm very disappointed with dstv accounts department they've been charging me interest for the account that I know nothing about. I've been trying to enquire about it, but no one is willing to help me. My dstv subscription is annually paid and my funeral policy is a monthly payment which I pay every month, I've been trying to solve this problem for too long without success. Can someone there who knows to do his or her job to help me.