working without pay

my little sister worked in this store for 4 days as the staff was going on a holiday to durban for the weekend. but now as they are suppose to be paid pick n pays says they paids their money to the agency and the agency says they paid their money to their supervisor's account for him to pay them, the supervisor is now missing. and the have not received the money. pick and pay should pay this people and they will sort it out withe the agency because they worked for pick and pay and now when they are supposed to be paid they are told about the agency. this is not fair they used their more for transport and to go to work they came home around 10pm in somedays because the couldnt find transport now they are supposed to be paid the little money they worked for and they are not. this is not fair that people are taking advantage of unemployed people like this. pick and pay must intervine and pay them.