Vodacom - security company or service provider.

I have Vodacom services that are no longer in use. From experience I know, that if you want to cancel services with Vodacom you have to send an email as you will not be helped if you only call in to cancel. So, I sent an email to cancel two numbers. Next thing, I get a sms that I have to call the cancellations department. I do not understand why I should call in as I have sent all the information through by mail. I decided to call anyway only to be confronted to answer five security questions before I will be helped. Now I have an issue with this as I have sent the information from my email which is on their system. They send me a message to my mobile number which I respond to, hence I have a problem with answering all these questions while at the same time the ********s still get it right to perform *****ulent activities. I am feeling more and more that Vodacom should not be the service provider of choice. Now if Vodacom wants to have a lot trouble from my side, they must take money for the services on which I have requested cancellation!!