Robbing people

There's a car competition going on at checkers and checkers hyper. So once you buy you get a slip showing how many entries you qualify for to win 1 of 150 cars. And then to complete your entry you sms or dial a number. My complaint is that the cashers take some of the competition slips for themselves. Eg: if I buy for R600 I qualify for 13 entries but the cashers don't give all the 13 slips to the customer they take some for themselves which is wrong.