Sales consultant **** to get customer to upgrade

I upgraded my contract and the sales consultant **** to me about the billing after i asked him i think twice to confirm that there will be no extra charges and he confirmed. Not only did he lie about that but also **** about the start of my new contract. MTN loaded my new contract package while i was still on my old contract ( according to my understanding what the sales person confirmed) so i queried it and after 3 calls then only i was given the correct information and got the shock that i have to pay for basically both contract still. i would never have upgraded if i was told i must pay for 2 contracts. Why do MTN offer an early upgrade if the customer is still going to be paying for the current upgrades' device??? This is not the first time that i was advised / given the wrong information by an sales consultant when doing un upgrade. i have been an MTN customer for over a decade now.