Vodacom ***** and Add-on contracts

I have had a contract with Vodacom since approx Oct 2014. Early 2017 I was contacted by Vodacom regarding an add-on contract, which I declined. I thereafter realised that there were additional funds being deducted via debit order from my account. I contacted Vodacom to query the same and a second contract was indeed added to my name. I never agreed to this and never received a simcard. These debit orders have been deducted for longer than a year and upon querying for the third time, I was referred to their ***** department. On 16/07 Vodacom agreed to cancel the contracts and refund me a dismal sum in respect of the add-on product. This refund was calculated from Dec 2017 to July 2018 despite the contract being in place since approx June 2017. I was instructed to respond with my banking details but I instead queried the same by replying to ********** and ********** on 23/07 and again on 26/07, and have yet to receive any response. Absolutely shocking that: a) An add-on contract is in place without my consent b) It is a battle to get always get clarity from Vodacom, considering my first inquiry was in 2017