5 months overcharge for a service I didnt get

1 week passed and still 5 months of overcharge on a service I wanted and paid for less than that. I have been paying 5 months for a 4MB line with telkom and I only received a 2MB line. Now here is the thing that upsets me. First no response from a query I made. Then they tell me the problem is with me. The guy comes tells me everything is working more than fine. But he only tests a 2MB working so the problem is with Telkom itself.Great service from him. Then I line test even worse 1.7MB. I Phone my ISP the guy immediately tells me my Line with telkom shows only 2 MB and says the problem is with them. I again phone telkom lady helps me very nice and she tells me yess they have to reset the ports......so guess what...my internet is down to 0.90 MB. Worse than it was before. Here is the problem...no 1. No one said about crediting me back for overcharge on a fault on Telkoms Side that I paid for. 2. Im never ever late on payments! 3. Why if its a service that I pay for on time does Telkom not even phone after hello peter post to tell me they will solve it. This is a clear breach of contract and my lawyer is looking into this matter! Fix my damn line and refund me the money you owe me!