Vodacom, doing their best to get rid of customers

Vodacom is still insisting on leaving a contract open after made them aware that the unit does not work for my purpose. Instead of canceling the contract they insisted on trying to fix the error. This resulted in my cancelation days expiring. Over and above that, when I called to cancel they blocked my number and wanted me to pay a fee of R2 a minute to speak to the relevant people. I have since raised the matter many times on Hello Peter and Twitter but all I get is automated computer generated messages. I don't understand why Vodacom believes disgruntled customers are the best but they have lost my future business.