Poorly trained call center agents

I use to be a loyal customer with Cell C inspite of the unprofessional call center agents and bad connection. In the beginning I only had a Sim activation then was called by a agent that the wifi router was on a special which I took on contract for 24 months. After that I was called a few months down the line that I could upgrade. I said only if it don't exceed R500. 00 limit including my router as that's all I can afford in my budget. She assured me more than once that it was correct. I received a follow up call that a double debit will be deducted from my account as it's holiday and in the new year there won't be a debit until February which didn't happen. In December they took over R1003. 00 and January another R573.00. Then was told by another smooth talker agent that I'm confusing them recharging such a lot and another promotion was on offer 10gig for R80 on contract for 24 months. I still asked is this R80 for 24 months or only now and she said no it's on promotion if I act now for this special promotional price for 24 months. Which I did but when I got my statement and the debit went off it was 2 or 3 times more than what they quoted me over the phone. I called in to complain, sent e mails and went in store. When I went to the store the store consultant was very helpful and called Head office. I explained my whole complaint he then explained to the store consultant what he should do and he informed me that after I paid the current month's installment into The Nedbank account I must e mail proof of payment and my account query will be resolved. In future I will be paying less as I canceled the extra Data that was month to month as well. In the new month there was just a slight adjustment to my statement instead of R815. 00 they took off R694. 00. 2 months went by with my account fluctuating between R600 and R734. 00. There was also no mention on my statement of promotions. Last week after 2 months had lapsed after so called resolved query I received a sms that my account was in arears and that I need to sort it out or legal action will be taken. I was so upset as this was never what I signed up for and their *********** staff and mismanagement of my account has caused this way too high account that I now have to struggle to pay with my disability grant. I am so upset as Im also a lung and lupes patient besides being in a wheelchair and all this stress has exasperated my health condition.