Costs added to my account without my permission

I have a Vodacom internet ****le where I get 2GB data for R139pm, From December 2015 I suddenly pay R208pm, when I phoned Vodacom this morning they said that insurance has been added to my contract. The insurance was added by Lelonolo at the Centurion Chatz branch. I have never been to Chatz nor have I given permission to ad any insurance to my contract. The number for my ****le is ***.