Simple instruction difficult solution.

I am very disappointed will the staff and manager at this shop. I give them simple instruction but they cant understand but the continue to do the wrong thing. I asked to separate the bills as the other must go to my employer. She couldn't do it and she called her manager or supervisor Miranda who didn't take time to hear what I wanted and just went ahead and did the opposite. After she says it's not possible. I really cant believe their incompetence.