Vodacom charging for contract while on prepaid

After the mess up of trying to move to prepaid (https://www.hellopeter.com/vodacom/reviews/vodacom-move-to-prepaid-not-happening- ********** ) Vodacom is now charging me for the Smart XS plan even though I am on prepaid. I received an invoice stating that I will be charged for the contract at the end of this month. After calling the call centre and speaking to Mpumi (13 August) I was assured that Vodacom would get back to me in 7 days after they conclude their investigation. But I never received feedback and today I see the issue has been closed without anyone contacting me regarding this overcharging on the invoice. Ref 1- ********** **********