Contract overcharged

<p>i took a 2G data contract with Vodacom in March 2016 for R159 per month. they've charged me up to R5500 from my bank account. when i enquire the contract was not set on top-up. however eversince June i never had any data nor hear a word from vodacom. i would like to cancel this contract as it was never friendly towards me, i had missarable 3 months with them.</p>