Taking contract end end you will pay for services you have not used at telkom

I was due for an upgrade at Telkom their sales direct marketing called me on the 22nd of June which I agreed to take the upgrade. The handset was delivered on the 28th of June. I had to wait for the phone to be registered which was done on the 3rd of July. To my surprise when I got an invoice I was told that I am owing the handset for the 1st to the 30th of June .. I had I being told that when I accept delivery in the 28th if the month I will be liable to pay them for the whole month I would have waited for the handset to be delivered on the 1st of July. Now im sitting with an invoice with double amounts. The month of June 99 1-30 june. 99 for 1-30 July the old handset 1-30 June and month of July 1-30 July 99 for new handsset. I Called Telkom and explained that this is day light ******* now my account has doubled from the previous month. They said there's nothing they can do I am liable. In these economic times Telkom cannot Rob it's customers like this. I am also taking this issue to the consumer complaints Commission.