Blocked Cell C number

So, after my previous complaint regarding billing and accounts. It has come to my attention that Cell C has now blocked my sim. After my payment of R500 has been allocated to the correct account after 3 months, I've lost 3 months worth of data and free minutes. Today I tried making use of my Cell C number at it seems like the SIM card has been blocked completely. I need to get in contact with the correct person to speak to regarding cancelling this Cell C contract immediately. Cell C was at fault and I still get demands for money for the last three months. I am telling you now I'm not paying anything to Cell C anymore. I want to cancel this contract immediately or I will go legal