Missing Petrol Card

My husband got his new petrol card and as a precaution threw in R15's petrol, to test if the card works, and indeed the payment went through. He requested them to fill his tank and when he wanted to pay with the card the card was suddenly declined. Due to the time, he was unable to sort the problem with his employer and bank, so Steve (claiming to be Manager), kept my husband's petrol card. My husband told him that he will sort it out the following day (yesterday) and come back to collect the card after work. Everything was sorted and the card was confirmed to already be active. We got home late and my husband drove to Engen to pay and collect his petrol card, only to be informed that dear old Steve never pitched up for work yesterday and nobody at the garage knows anything about the card. It's missing. He drove back for a second time as we could not get hold of the garage and upon phoning Steve, he claimed he does not know where the card is, been very arrogant, when my husband told him he is going to lay a charge of theft against him and Engen, as it was responsibility to keep the card! Due to this my husband can loose his work and Engen and Steve will be held liable!