They broke a perfectly fine car

My wife took her car for a service and barely a week later the car broke down. Took the car back and found there was no oil in it. They filled it with oil and checked all the seals and serviced the turbo because the bearings might have damaged. Since then the car has gone back about 6 times. There is an oil leak they just can't seem to fix. The car is 5 years old and never had an issue until they got their hands on it.