fed up with cell c

We ugrade on my cell c contract first there was no samsung in stock so we phone to book for samsung note 4 after a week we phoned they told me they have one that nigth i went to upgrade they simply said sorry we dont have one in stock so we had to take the lg G3 so then they put met on 2 g smart chat so the tech was at my house testing my signal because i cant download on my sim we did a sim swap and everthing they told me its going to take 2 month to sort it out so we refues to pay because we pay each month and we are trying to sole this problem since november 2014 and we didnt make a payment thet block the phone please someone sort it out for me they noylt doing there job so why should we do it!!!