Still billing after cancelation

I had a 36 month contract with tracker that expired sometime a go and I was told I am on a month to month basics now. I called and cancelled my units in June but I am still getting billed for the units and I have phoned many times and tried email and still nothing. <br> <br> Why wasn't this cancelled when I asked everyone at the call centre are just rude and don't want to help and no one replies to emails. <br> <br> what a joke