Worst customer service of all mobile network providers

I cancelled a contract at MTN, it was also confirmed my email. The contract has not been cancelled, *** and *** only replies that they received my email, and how important their customers are. I have also tried to contact MTN via Facebook, they can not assist me, I have to contact ***. Customer service is completely useless as it is not possible to be in contact with a specific person, emails just goes into a mass account and nobody takes responsibilities of any cases.