Thabo do not know how to cancel a contract

On the 26th of May 2018 I phone Vodacom to cancel my 3G. I spoke to Thabo and he assured me that he will cancel it. He provided me with a reference number 1/ ********** ********** . I also received an sms. Yesterday at 29th June 2018 I got a call from Zakhele that asked me if I wish to upgrade, I then inform her that I cancelled it on the 26th of May 2018. He then advised me nothing is cancelled. He then went and cancelled it for a second time and provided me with a new reference number 1/ ********** ********** . I am truly unhappy with this as Thabo confirmed he cancelled it but never did. I want this to be sorted out immediately and want my D/O to be reversed.