Wrong change given

This morning I went to the shop to buy 3 small items that had cost R34.47, I gave the teller a hundred rand note to pay. She then gave me R15.60 change instead of R65.60. As I was in a hurry for my doctor's appointment I took the change and quickly rush out but something was telling me that there is something not right with the change. While outside I rechecked the change and slip and realise that she said I gave her R50 instead of a R100, I then immediately went back to the shop and showed her the mistake she did and to my surprise she told me that I gave her R50 not R100. She then called the controller who then called a security and asked her to do spot check in a certain room (whatever that means) When they came back they told me that there is no R50 extra in the money she has. I believe there is another way that the shop can use to see for sure that I gave that lady R100 not R50. I just wonder how many people has had a problem like mine and did not get helped. <br> <br> Worried<br> <br> Helen Masina