Misleading sale amount

My Name is *****doMapipa I have a contract account with vodacom which suppose to be terminated end of December 2018 but an agent from vodacom chatz in Pretoria called me saying I'm due for an upgrade, I then agreed on the deal of a laptop with a condition emphasizing that I'm not willing to pay more than my monthly subscription of R611.58. She then assured me it will be less if not the same amount but to my surprise my subscription went up to R788. On our conversation I did ask her she was aware that I'm stil paying for the 2 handsets,She said yes. This had happened on the 18 of September 2018 I then received an HP laptop as promised on the 28 September 2018 via RAM. On the 3rd of October 2018 I called vodacom customer care to find out how much will be debited from my account they asked me to call on the 5th of October 2018. l did and was told I will pay R788 I log a complain service request which was never attended to. I'm very much disappointed with the fact that I was mislead and no one seem to be liable with such act up until today because the laptop is still in my posession even though I've asked for it to be picked up and reverse the changes that were made on my account based on the fact that I cannot afford to pay such an amount.