CHANGING YOUR CELLPHONE CONTRACT

I recently took out a new line (I have 5 lines with Vodacom) in order to purchase an new IPhone 6. I did this at Istore the Glen. I already make use of a number with Vodacom that has a monthly Data bundle of R98 that I now found out constitutes a 'contract' and thus I could not upgrade it as it was not due for an upgrade this is why I took out a new line. Immediately after taking out this new line I went back and asked if I could change the selected contract to the cheapest contract. I phoned and e-mailed Vodacom who told me I could do this. however I am now told by the sales agent that this is not possible f! This is grossly unfair, how can I not be able to change my contract immediately after taking it out? If I have realised the selected contract is not suitable to my needs I should certainly be able to rectify that especially within 24 hours of taking the contract out! Vodacom clearly does not care about meeting their clients needs or being fair. We are just numbers or rather debit orders to them.<br>