Closing an account with Edgar's

How can I close my Edgar's account? I am tired of going into the store to try and close my Edgar's account. I have had the account for 42yrs and I don't use it anymore. Yet, every month I get charged interest. You can't close your account unless it's paid in full. So it's a vicious circle, because there is always a balance. I have tried phoning, and to get through to them is another story. I eventually got through to them last month and after about 10mins was told my account was now closed and I would get a call or email stating it was closed. Needless to say nothing was received, except I get another statement today, saying I owe R57. 98. PLEASE help I really need to get this finalized.