Telkom service is disappointing

I am absolutely furious with Telkom we app**** for uncapped wifi for R499 a month they installed it in April is hasn't worked ever since i had to use my own money running around to telkom store to try and get it fixed only to find out the problem was not with the device there was a problem with the line after months of calling telkom to report this numerous times it was eventually finally fixed in the month of july and now i get a bill for R3500 and they are not answering my calls so i can find out how exactly did they get to that amount