Cancellation of Vodacom contract

About 2 months ago I want to cancel my vodacom simcard that I used for internet. I was at a Vodacom shop in Langenhovenpark. They phoned headoffice and the lady their told me that I cant do it because I upgrade and have to wait for 2 years. I could’nt understand it because I did’nt do a upgrade. Then they saw on the computer that it was upgraded by a lady from the callcentre, (Mthombenu) on 14/03/2018 at 08:43. I cant remember anything about it. Now nobody of vodacom cant help me. I feel that Vodacom have to solve this problem because I did’nt give permission for the upgrade. My card no is ********** 1405.