Unable to complete requested upgrade

I have been struggling with an upgrade since 17 October 2017. I am due for an upgrade on a smartinternet deal, and so went in store(Vaal Mall, Vanderbijlpark) to do the upgrade. There the sales person Sondo tells us that the deal cannot be changed from data to voice. I then go online and do the enquiry/ upgrade online and get a confirmation email from Kelebogile Ma***o to say that the deal can be put through i should go to the store again. For two weeks going there almost everyday, trying to phone service people to help and standing in long cues, the other sales lady Tanya really tried to help me, but still no feedback from her. Then again today i went to the Vaal Mall store in Vanderbijlpark and ask another male sales person to assist me, He went to the back and told me again that the upgrade cannot be done and I should wait the contract out or apply for a new contract. So why does a person( Kelebogile) tell me that my upgrade can be done but then at the store they cant help me, couldnt they just have told me from the beginning we cannot help you do not waste your time. Why do they even give the option for upgrade if you cannot upgrade? I am dissapointed in the service and the false hope that was given to me. So therefore i am finishing my contract which ends January, and cancelling it.