Bad customer service

I took a contract with vodacom and told them that I want it capped to only the benefits received every month. I did not want to pay any additional fees. I noticed an additional payment on my billing statement.i do not use this Sim card for anything more than calls and internet yet I was told I subscribed to a calender and suddenly told that I have an open line when I specifically asked told them that I do not want an open line! I do not want any additional charges!