Is SPUR ****ming customers?

Three of us had breakfast at SPUR (King Shaka International Airport). The bill was R534. The waitress processed the card payment, tore off the slip and said the transaction had "failed". Payment was made again and this time the payment succeeded but when the phone pinged twice, two payments had been processed, one was for R300 and the other payment was for the correct amount of R534. Fortunately the first payment notification of R300 went through to the cell phone immediately and was queried at the Spur front desk. A refund was made. We suspect that Spur might be ****ming airport visitors.