Airtime Refund

I’ve been taken from pillar to post by Vodacom. I bought airtime for a number that is not working. They checked and saw that the number is not working and the airtime has not been used but they are refusing to refund airtime. They asked me to call FNB and FNB is referring me back to Vodacom of which it makes sense that FNB is not in a position to trace if the airtime has been used or not and only Vodacom can see that. When I asked why they can’t refund the airtime they not giving me the reasons they only say they can’t. When the take airtime out of our bought airtime they are able to replace but now they can’t. Why the cant refund airtime that they confirmed has not been used? I need them to refund the airtime for a simple reason that the airtime is still available and the number that the airtime has been transferred to, is not working currently. The A8-A1AA-PQ15 & A8-A1AA-PQ15K. Vodacom ref number RN ********** 3013. Can I get some answers?