Extra cash payment asked

I have been using the Total car wash in Rustenburg Cashan every week for years, the past few months I am being told they need extra Cash payments to clean my car, I pay for my cash wash and need to pay the people cleaning an extra R50 cash (not allowed to swipe with the carwash payment) this is becoming a problem for me and they have a really bad attitude and don't clean properly if you dont pay.