UNHAPPY CUSTOMER Poor Customer service

I have been struggling with the survives of Vodacom for the past 3 years, I have added airtime on Sunday and it just vanished through thin air. I have considered to cancel with the provider. I have had so many problems I even changed my address by phoning them and they still have not done that in the past 2 years so I gave up to even try to speak to them ever again then they phone me every month to sell a product that I am not interested in.