Unknown additional charge to contract

Recently got a cellphone contract with Vodacom, this is not as a first time client, I got a handset installment with comprehensive cellphone cover, a month later my invoice states an additional “Vodasure Asset Cover”, I was never contacted with regards to this cover, I don’t know what it entails,no paper work was sent to me when this was “taken up” and I’ve been trying tirelessly to cancel whatever this cover is with no luck, it’s incredibly infuriating to have to pay for something I was never informed about nor have any idea what it covers, I need this cancelled as in yesterday.