Debiting my account without my consent

I app**** for contact tablet on Dec 2015 I returned the package back 2days after delivery and I cancelled the contract they debited me R160.50 I reversed the transaction with my bank again they debited me 20 jan 2016 amount of R160.00 .I called cancellation Department they told me contract it cancelled permanently they advised thet do not kknow why I was debited, sent email to customer service they have responded to my email its 7days now and still nothing. CELL C is reaping people off and I wany my money back. What a sick company