Impossible to close RCS account

I have paid up my account in full and email RCS numerous times to close the account. I have tried calling the call center which no one answers and when they do they transfer me which just ends up cutting the call. I received a statement showing I owe admin and interest fees which makes no sense as I have already paid the account in full. This needs to be resolved and the account closed, and with no apparent way to get through to these people how am I supposed to do that?