Being billed for a service they cannot offer

I am currently on a 10meg line with Telkom ADSL. The sad part is Telkom can only offer a 2meg line in our area. So for months we have been paying for a 10 meg yet only getting a 2meg. I was on hold for 54 minutes last week Friday with no help. I called this morning and have now been transferred to another line without any communication, no reference number nothing. On hold waiting patiently as I type, this is ridiculous.... Can someone from Telkom simply do the following:<br> 1. Downgrade my bill to reflect the correct amount as you are billing me for a service you cannot provide.<br> 2. Credit me with the amounts I have overpaid for the past 6 months or so.