Poor customer service and *********** technicians at Williams Hunt The Glen

I took my Chevrolet Sonic at Williams Hunt - The Glen for 75 000 km service and they kept my car for 4 days. It was my first time to experience such a bad customer care. their team is rude, unprofessional and ***********. Within a month after service I noticed that the oil and the anti freezer was low, decided to refill. Couple of weeks later I took the car to Williams Hunt The Glen to complain, he just refilled the anti freezer that’s all. To cut the story short I had to refill oil and anti freezer twice in a month from my pocket. I realized that the car is leaking/ dropping oil and the engine is oily. Whenever I call them to inform them of my situation they say the are fully booked. I’m tired ti fight them and really don’t know what to do or where to go. Frustrated customer