Very very upset with the treatment from Vodacom

I was promised on the 7th September that my debit date has been rectified to the 15th, the debit did not go through this month and today I call Vodacom to find out why they did not take their money I am told that my debit date is the last day of the month. Who changed my debit date from 15 to last day of the month because it seems like it is difficult to change it back to the 15th. I am told that the R100 that Lucian promised me that it will be taken off is still on my account for non payment. I am also told by the consultant that I must go to the Vodacom shop and pay there, I am not going to run around for Vodacom's fault and negligence.

If Vodacom tries to take money again on the last day of the month, there will be no money and it is not my fault that the consultants are *********** and they cannot change the debit date back to the 15th as per my initial request.

I want Vodacom to cancel my contract and collect their phone where it was delivered as I cannot be forcing them to take their money, it is not my responsibility. My credit score is not good due to their negligence.