Incorrect billing

I was offered an upgrade on my smart home 5g @ R299 per month to 10g @ R299 per month. Nothing ever happened. Jan the special was offered. It was never processed. Eventually after many reports and complaints someone else from a business division of Telkom helped me. Now three months down the line I am been billed for admin chargers R400 and penalty fees R840 totaling R1240 which was never advised by the sales consultant who offered the upgrade. The reason is because I am upgrading before the contract expired. Why tell me Telkom do you penalize customers for doing un upgrade. So you are catching people by offering these specials and leaving out the fine print. Yes please upgrade but it's going to cost you. Logic says if I want the 10g per month means I want to do business with Telkom I'm not going anywhere. But to charge me for a years contract left because Telkom is offering a special, that does not work for me. I am definitely going to look into cell c buying my contract out for me. I don't want to do business with Telkom anymore. Then when I speak to a consultant I am told but you agreed to it. No I didn't agree to the additional charges because no one mentioned them.