No support from Telkom

We upgraded to a bigger data package a month ago, we have gone from having 43M download speed to 0.06M not enough to do our work. We have logged this with Telkom every three days for the last month, no technical support have come out, no feedback given. We were told yesterday that they are now using Vodacom instead of Mtn, we have NO vodacom coverage in our area, that is why we moved to them in the first place. If this is the case we need our contract cancelled and they can take their router back. Why do they sell something that they cannot provide? It is impossible to cancel a contract as the legal department's details are not available anywhere. Can someone please give me details of who to contact.