Wrong change

I went to the store two months ago and was given the wrong change. R10 shortpaid. When i told the cashier i had to open my wallet to show him that i didn,t have it in my purse. Today i went there again. Same male cashier. I was given a hand full of change and held it out to him to again show him it was R5 short. He immediately gave it to me and said sorry. I find it strange that the same cashier twice in a row would make amistake with my change. I would not buy there again.