Billed for a service I did not receive

I am completely fed up with Mweb. I wanted to switch to the ADSL service through Mweb from the current capped service with a CellC line. In this regard, I had given notice to terminate the month-to-month contract. I was advised that for the month of September 2015, I would be billed but that no data would be loaded onto the Modem. I am really upset because I received a bill showing that I used this modem in the month of September and exceeded usage, starting off from 1 September 2015 until 21 September 2015, which is completely incorrect. I was given a ridiculous Excel sheet showing my so-called usage, with at times 50 usage sessions in one day, curiously, even though I am at work and there is no one at home except my dog! I have written to them several times, but it appears that my complaint is not being taken seriously, all they do is send me a set of terms and conditions about monitoring of usage. I am convinced that they had reallocated this same line to someone else and that they are billing me for it. At any rate my plan is to badmouth them as much as possible. They very bad service providers and don't care about their customers, I will definitely NEVER EVER RECOMMEND THEM.