Telkom double billing

I am at my wits end. I have been double billed for over a year. I have tried every channel regarding my billing dispute and am told that my account will be rectified, which never happens. At once stage I was billed for two 4mb ADSL lines. Then I switched to fibre and have since been billed for the old 4mb ADSL line in addition to my Fibre line. Till now, I did not want to be refunded, I just wanted to double billing to be rectified. I then landed up paying my double billed account every month to avoid suspension. I now wish to have my account rectified and to be refunded for more than a year of double billing. I refuse to pay another account before this issues is settled. I do not know who to turn to next.