Unresolved dispute

About 4 weeks ago I logged a bill dispute with Telkom because for the past 20 months I have been paying for a 4Meg ADSL line, but my line always had speed issues. Only to find out when I went to the Telkom store that my area offers a maximum speed of 2Megs so I've been paying extra for nothing. After my dispute was logged I was told to downgrade my line before any credits can be made, which I did on 07/03/2016. I phoned Telkom on 26/03/2016 to follow up and was told the downgrade is in progress, and the credit would be done as soon as it is complete. Now my line is disconnected. No credit made, no feedback on my query. This is so frustrating and calling Telkom is a torrid nightmare. You hold for hours and their staff is rude