Incorrect Billing - Bad Internet Service

In February 2015 I renewed my ADSL data connection at the Centurion Telkom store and they gave me a new modem with new package which is cheaper. Four months later they still continue to charge me for my old Internet connection and the new one. I logged faults and raised a dispute on the bill, but I am still being charged double. Telkom phoned me to ask if I wanted to upgrade my ADSL to a 4MB/s line and told them how unhappy I was, but they suggested I go back to the Telkom store. Which I did, and they could do nothing more than I already had done by logging a dispute on the account. They suggested I deduct the extra amount, but when I said then Telkom will disconnect me the lady didn't reply.<br> I also struggled to get my new modem to work for 3 months. I just could not get through to their help line when I was at home. The previous time I did this it was much better, that's why I decided to use Telkom Internet. Service has degraded significantly. I will never use Telkom Internet again.