Payment over a suspended line

My account was suspended over non payment however I kept getting billed for it. The first month after suspension , when I got billed for it .I complained about it and I was told that the issue was being escalated and a consultant will contact me. However this didn't not happen , four months and several complaints later I'm still getting billed for my line and nothing had been done to resolve my issue. Finally I went to a Telkom centre and I was notified that they keep billing you even when the account is suspended . Which does not make sense because the account is suspended , and even if I was to continue to get billed it should only be for the line and not the adsl that I am not using. During all this I was out of the country and I notified Telkom of that fact before I left and asked for advise on what To do with my line as I did not want to pay for months that I would be away for . I was told to call the billing department however whenever I tried to contact them no-one answered. I am extremely frustrated by this and at this point not willing to pay for those 4months.