Breach of contract

I bought a top up tablet on contract on the 13th of feb and I signed the contract but it was never activated and went back on the 14th to query whays happening and they promised me that it will be fine bu the end of business day of the 14th.monday the 16th I called them cause it was still not active, onlu to find a shock of my life cause they told me I must pay R852.00 first something that was noy on my contract.so vodacom is misleading clients with their ********** deals. I want jistice to get the deal I signed for.