Over charged

Me and a colleague went to PnP, we were in hurry cause we had break of 30 minutes, we wanted something that we could eat quickly so opted for pies....the ticketing on all pies is R22.50 and we asked the short man if that's the price he said yes...but we charged R26.99 each for burger pies...the kind till operator called a lady whom I think was an MoD or supervisor to assist but that lady said they are on promotion ,we then told her if thier on promotion there would have been a promotion ticket by that section but there just a printed A4 paper stating the price on the pies....we asked another customer behind us to borrow us her smart shopper card since we didn't have ours, it was swiped on my colleagues transaction and the pies weren't on promotion. The MoD or supervisor just left us at the till point...