Did not sign up but was charged

I activated the 14 trial for Showmax but did not subscribe, as the streaming quality was very bad. I received an email from Showmax saying that I will be charged on my Vodacom account. I phoned Vodacom to tell them not to charge me as I have not subscribed and do not want to subscribe. I was on the phone for a very long time, after which they assured me that I am not subscribed to and will not be billed for Showmax. I just received a message from Showmax saying I was charged and R99 is gone from my air time.