Duplicate transaction not Refunded by VM Truck stop

I am very disappointed with the service received at this fuel Station on 31st October 2019. I put in fuel and used my debt card to pay , on payment I was told by the attendant that the transaction did not go through, I did not receive a slip saying it was declined and my bank account reflected the debit. The attendant and manager insisted that I do another transaction and that the first transaction would reverse in 24hrs and if not they'd refund me. After telephone conversations with the manager and e-mails with the owner as at today 25/11/19 I have not heard from them or been refunded. I don't know who can afford to loose hard earned money because these businesses are not concerned about the little person.