Cancellation of contract

I was sold a subscription for additional data a month. Did not receive any data since the start of subscription but charged R127 every month on Edgars account. I have tried on numerous occasions at Edgar's stores to cancel this contract but to no avail. It seems no one at Edgar's store can get a hold of RMCS to cancel this contract. I have tried to contact RMCS directly via the following numbers ********** and ********** provided to me at Edgar's but no one picks up after holding for more than 20 minutes. Could someone please help