National Tire & Battery [NTB] review: mechanical repairs

On sept. 4, 2019 I took my 2003 cavalier into ntb in crestwood, ill. Because the check engine light was on. I was there for three hours and was told that they had replaced a valve. I was charged $450. On sept. 8, 2019, the light went on again. I took it back in
On sept. 10, 2019. I was told that the valve was faulty and a new one was installed.
I was not charged. Today, sept. 16, 2019 the check engine light went on yet again.
I now have an appointment to bring it back tomorrow at 11 o'clock. I was told that the same mechanic will be working on it... If he knew what he was doing I wouldn't have had to make a second and now a third trip back. What the results will be after tomorrow's visit are unknown. But I have to say that the service I am receiving is
Grossly inadequate and should this problem ever be corrected I will never return to ntb. I will inform my family, friends, and even any strangers I meet to stay far, far away from there.