Overpaid, double swipe to machine error - NOW a headache to get refunded,

Although I loved the experience at Avianto's Cielo Cafe this past weekend, it has been soured by unprofessional behavior, we overpaid on the bill as the card machine did not work, and we were told it will likely be reversed. It has not! We called the restaurant none of the managers in at 11:00 am this morning, I asked to be called back, but nothing, I called again and get a ringing phone. Further to this, we have been asked to provide proof, of when the manager on Saturday clearly said that he will personally follow up and reverse it, not there is the inconvenience of having to send bank statements, etc. And still, no follow-up from the managers. This is just poor for such an upmarket venue. Please refund us what was overpaid!