Vodacom Sales taking advantage of elderly lack of understanding

I have an elderly father on a pension. He has been a Vodacom customer for many years. To assist in cutting costs and getting more value for money, when his current contracts were finished, we planned to change to a sim only SmartXS contract for R129 a month and a Sim only Data Contract for 10GB for R229. This was done online in June 2018. The monthly total should have been R 358. Instead of automated online, a call center agent needed to contact him to complete it.

Instead his existing contract was renewed as SmartX with the existing charges which is between R400 - R500 a month, he has been called by the sales staff recently and been sold a uChoose Flexi 220 contract for a dual sim phone he does not have or need for R159 and his 5GB data contract was renewed for R199 and not cancelled. So instead of having affordable Vodacom cell and data contracts he is looking at a bill of over R1000 a month.

This is taking advantage of a vulnerable person who does not really understand what is being sold and even though he agreed telepathically to it the contacts, he is 78 and not tech savvy and it will sound like a good idea without fully understanding the costs. He is a loyal customer and has never used any other provider. He has become ill over the last few months and becomes confused and does not fully understand what he is contracted into.

How can I urgently resolve this? He cannot afford this amount a month and should not be bound into four two year contracts which will put him in a financial crisis.