Telkom raising installments monthly without notification or communication. Unacceptable

Good day, I have telkom wifi and have been paying a certain amount for more than a year. Telkom mobile number in question is ***. Aug 2020 my account went up from R359 to R542. I called Telkom took me three calls and yet still i was not able to speak to a consultant to tell me why my installment went up. Today i received another mail from telkom that my account for september is R620. No communication, no notification. I have been trying to get hold of them but no luck. Their customer service is really bad when you need to get in contact with them but when they want to sell you something they know and and when to get hold of a person. I need answers please.