Telkom line cancelled, still getting charged for it ,6 months gone!!!!!

6 months ago I sent cancellation form,along with all the relevant documents for *** RGS Batteries as we were moving premises and on the new premises Telkom said there is no copper line. The following month I received my last account statement which I paid and thought this is the end with Telkom. Unfortunately every month I am still getting billed for a service which DOES NOT exist. The line is non existent we are not on these premises the line was cancelled. I call Telkom every month explaining to them that the line was cancelled they say we can see that on our system and yet a month later same thing comes, not only that the bill escalates but it increases ,now its sitting on R4570,next month it will be R5500, is it that difficult to do your job TELKOM you are a useless company,stop bothering me ,the line is cancelled and the conversations are recorded.