Contract changed with no communication to client

Hi <br> <br> Cell C changed my data contract without contacting me or sending me any communication. I have been holding to speak to an agent at the Cancellations department for ages. <br> <br> I spoke to Sizwe on 08 Feb 2016 at 10:52, he stated that my contract was changed on 15 January 2016.<br> <br> I am not going to pay another cent to Cell C. I would like this contract to be cancelled today and no further debit orders should go through on my account.