Billing & Accounts

I visited the restaurant last week Thursday, when making payment I was told that their speed point had a malfunction on a number of attempts, the teller told us to pay cash which I did. After leaving the restaurant I got a notification that the payment went through, which meant that we paid twice , I called them on Friday morning and explained my story and they are just giving me run arounds about getting my refund, to date I haven't received my money as they claim that the amount hasn't cleared on their side although I sent through my bank statement as proof of payment.

Please kindly assist