UNHAPPY WITH THE BILLING ON MY SUSPENDED ACCOUNT

I had a month-to-month Wi-Fi account with rain, which got suspended when a payment did not go through. But the amount I owed kept growing though the service was long suspended. That account is now R1916.00 I have contacted their support a couple of times to try & understand how they keep billing a suspended account and the people I spoke to kept emphasizing that I need to pay the R1916.00. I am not paying that much amount because they had long cut the service. I am interested in getting the 101 home Wi-Fi that they have but first I need them to resolve the R1916 issue first.