Contract Upgrade

I have had a contract with vodacom for 2 years now, last year in October i got a call from a consultant in vodacom south gate that my phone was due for upgrade and i told them no i was not interested, i got 5 calls about this offer and i didn't upgrade, one day i decided to go to vodacom cresta to enquire but upgrading my phone and they told me i could do it and would not pay anything extra. went back home to decide which phone i wanted to upgrade to then i made the decision, last year november i went back to vodacom cresta to upgrade to an iphone 7plus but was told vodacom cresta does not have stock i could go do my upgrade at istore cresta. Got to iphone and some lady assisted me, before we could do anything i asked her if i was gona pay extra and she said No, haven't said that every consultant i spoke to i asked about paying extra and they said No , You wont pay extra. From the guy from southgate that called me about this upgrade. Now i'm getting sms's that my account is due and they blocking my phone because i'm owing an amount for my other phones. I repeat i asked a 100 times if i would pay anything extra if i upgraded and the answer was NO. from a thousand consultants, this just tells me that sales are more important than a customer. I can not afford to pay double for a phone , that's just unfair and now when i complain i am not "No mam , there's nothing we can do about it".