How to Report a Gas Station Locally?

My vehicle is a 2005 Infiniti G35 which requires only 91 octane.

About a month ago I got a full tank of fuel at a 76 gas station and after 10 minutes of driving my car

lost power

check engine light came on, (Ran the code it said it was the throttle position sensor)

and it would occasionally die for no reason while im driving

15 gallons of fked up fuel later......

After running almost empty I got gas at Chevron and after 30 minutes all my problems went away I felt like the car had more power, check engine light was gone, and it didnt die anymore. So I thought to myself it had to be the fuel because that was the only thing that could of caused my car to act all weird.

Now today I decided to give that 76 another chance and only got about 5 gallons( i was running low) and after 15 minutes of driving all that weird stuff came back, engine light came back on, car had like a hard time trying to speed on the freeway and I almost crashed when the car even died while I was going 65 on the freeway because the steering wheel locked.

I am for certain its the gas, they are putting 89 or 87 instead of 91 octane in their pumps. I already made a complaint to the 76 corporate office but I want to know is there a local place where they can go and check this place out.