Incorrect debit order charge on a 24 month contract which I cannot get reversed.

I entered into a new 24 month Vodacom contract for 200min airtime and 1Gig of data in March 2022. The man at the call centre at Vodacom charged me R259, which was a substantial increase from R209 which I had paid the previous contract period. After the first month the debit order went up to R275, and after 3 months to R365.99. I have tried on four different occasions and many long waiting periods with different departments to get this fixed with a credit to my account. I am now totally desperate. I actually need a new device and do not want to enter into a new contract before I have sorted out the current problem. I am so mad with Vodacom Their service is totally unacceptable, and whilst their staff seem willing to sort out the problem, they all tell me they need to go to the back office, or escalate and then that's the last thing I hear. This is unacceptable service and a company like Vodacom with business ethics like I am experiencing should simply NOT even be in business.