Engen Garage Carnival sells expired Airtime vouchers

Engen Garage trading as Carnival S.S near Carnival city Sold me an expired airtime Voucher,a voucher that expired last year October as per telkom mobiles call centre and the cashier By the name of Fana had the nerve to tell me he WONT refund me or issue another voucher as there are no returns on vouchers after the call centre agent has explained to him that the voucher is EXPIRED. He then rudely told the call centre agent that she doesn’t know what she is talking about and he refused to call his manager and threatened to beat me up as I know too much of my rights as a consumer. I am going to make this whole thing viral all over social media so people can see how pathetic the service is at that Service station