Stay Away from Cell C Contract

I had a contract of two years with cell c, then they offer me to pay R49 for 500mb data contract I used it for one months then I cancelled they told me I will still pay R49 that was not a problem because I wanted to get out of them permanently. At end of the month after I cancelled my contract they charge me R119 I don't know for what I reverse it. Then they block my number without any explanation and I received an email from hpd attorney's concerning my unpaid amount.