Billing query

This is the worst service from ay service provider. I took up a new contract, upon delivery it came with 2 Sims cards. When I called the call center to query this, I was told this is a promotion sim, and won't be paying for it. However for the past 6 or 7 months they have been billing me for such card. I've called vodacom over 6 times to get this sorted. Every advisor tells me it's not their department.. This or that... Im so gatvol with the lack of accountability the company refuses to take. I've asked for the recording and my full refund. And everytime every person will tell me they escalated it and will come back to me.. The ****test service ever.