Charged for Telkom's error

I'm really tired of Telkom's bad customer service, for the past 3 months they have been charging me for add on free me bundles on my portable WiFi router contract. I have called so many times and it either I get told they are investigating who loaded the bundle or someone will call me back and the last time I was told that the issue was sorted and sent thru to accounts for refunds however today is the 1st and once again the add on bundles have been loaded once again and they will charge me once again. To make matters worse I'm paying for something I can't use. They loaded Telkom call minutes and SMSes to a WiFi router. I have used Telkom for years now and definitely this contract is my last.