Had a flat tire on the front driver side on camaro. I have wide tires all around. Tire store didnt have my width to match my other tires so they sold me a thinner tire which is very noticeable if you look at it in the front. They said it is the same size just thinner. They said it will not hurt driving with a thinner tire. Is this true?
No! If you were limiting your driving and using it as a spare, you would be ok until you got the correct tire. But that's not the case here from what you told me. This is very dangerous.
This will affect....
It can damage your differential and axle. It will affect on your braking, turning, handling and control.
Your tire will have a different grip / contact patch on the road which affects how it turns and handles in turns. It will create a different foot print on the road and the less traction will cause braking, control and handling issues for sure.
You must always have the same size tire per axle. Unless it is a 4wd or awd, then all tires must be the same size.
And must likely you have a different tire traction pattern which will cause handling and braking issues and use more gas as the different tractions will work against each other. Tires have different patterns, sipes, grooves, etc. If they are different they will not work as design.
You need to take that tire back, demand a full refund, but a spare on and go someplace else and order one. Even online. If they refuse, then I would complain to the corporate office, BBB or even state attorney office.
Another thing to look at and you didn't say, is the new tire a different PSI? If so, that is a no no for almost the same reasons.
I wish you the best of luck as you fix this issue that they created. Someone doesn't know anything about tires.