Billed for October while only started using their service in November

I got a call from a sales person from Telkom offering me a data deal of 40 Gig, 20 day and 20 night at R269 a month. I considered it a good offer. It was before the 20th October. I was told the delivery period will be 3 to 5 days. It took them 2 weeks to deliver. I got it on the 1st of November and they actived it on the 2nd. On the 10th November I got a statement for my bill for end of November. It included charges for October and posting fee. To my surprise why should I be charged for October while only started using the service in November? Why charged for posting the statement when I requested them to email it to me? I called them and they told me they will investigate and get back to me within 48 hours but it's been a week now. Incident number: ********** 4. Bad service on first month, what must I expect in the next 24 months the duration of the contract? Because they never honour their contract, can I also pay for what I've used and I cancel the contract?