Shake Shack Receipt in Hand but No Food and No Refund

On April 27, 2026, I placed an order at the Shake Shack branch in İstinyePark totaling approximately $15 and paid by credit card. After the transaction, I received my receipt — receipt number 0044. Despite waiting about ten minutes, my order was never brought out.
When I asked what was happening, I was told that the payment had not "come through" to the kitchen side and was asked to pay $15 again. I naturally refused to pay a second time and requested a cancellation and refund of my existing payment. I was then told they could not issue a cash refund, that the matter would be reported to headquarters, and that my refund would be processed by headquarters and returned to me.
Ten days have now passed and there is no refund showing in my bank account or on my statement. During this entire time, no one has called me, and I have received no apology or update of any kind. I have also been unable to find a reliable way to contact the company online.
I am requesting that the approximately $15 I paid be refunded in full and permanently to the credit card that was charged, as soon as possible.