Unqualified mechanics

I brought my car in for service and then after a few days my car was making a loud and funny sound like something isnt tight. I took the car back to Bosch car service at tollgate road in durban and found out there is a oil leak and the car is running on low oil.if my headgasket is damaged who's expense should it be to fix.They asked for me to leave the car but they cannot make means to take me home I'm stuck waiting for my vehicle.