Paying for service from May which I did not have until August

In May we upgraded our speed. Two weeks later I received a bill for the new speed. I queried the bill because we did not have the upgrade yet. They kept saying I have to pay for the speed from date of request. I had to eventually follow up with Telkom ADSL myself and after the Telkom guys was here 6 times, by August we still did not have the increased speed. I called Mweb and advised them that I want to cancel because I am not happy to pay for something I do not have. They then logged a fault with Telkom and telkom finally fixed it. The Mweb technician said he could see that we never had the increased speed since May and that the only reason they were billing us the increased speed was because Telkom was billing them. But he said the record reflected that we never had the speed and that they would credit us. Mweb then advised they will credit us a few rands for the week but not since May because aparently there is no reference number for my complaint in May? Three months of stress and struggle and they still wanna deny us a credit for a service that we did not have. SO FRUSTRATED but searching for a new service provider :(