Non performance

I entered into a second cellphone contract on 23 November 2018 at Vodacom Wingtip crossing. The person who assisted me was Estiaan. The contract was cancelled the following day as they couldn’t get it to work after several visits to the store. They took the sim card of which the invoice is attached and told me that the money will be refunded. The refund never happened, and I was obliged to visit the store on a monthly basis to query the situation. My visit to the store was followed up by a call to Vodacom and after being transferred to several departments I received the same advice which was that the store should resolve my problem. I have now paid for a contract for nearly 18 months of which I had no use