2016 Chevrolet Malibu occasionally doesn’t turn off

Occasionally, when I push the ignition button to turn it off, it doesn’t turn off. I get an error message that advises me to put the car in Park (which of course I’ve done). It has happened on and off beginning about a year after I got the car in September 2016, and I’ve tried everything I can to stop it from happening, including slowly putting the car in Park, jamming it into Park, going back and forth from Park to Reverse, and letting it sit for a minute with my foot on the brake before putting it into Park, to give it time to register that it’s actually in Park. It seems to happen regularly for a while, then not for a time.
I looked it up online and it seems to be a common problem with these models, but nobody seems to have a sure-fire fix. I’ve called the dealership multiple times but cannot get them to call me back. Any suggestions?

I suspect there’s a problem with the neutral safety switch, which normally tells the car that it’s okay to engage the starter. Your car thinks it’s still in gear so it’s disabled the ignition button. This would have been covered under your bumper-to-bumper warranty but that’s expired. Take the car to the dealer so they can’t ignore you, don’t just call. If you don’t get anywhere there’s a number for GM corporate in your Owner’s Manual. Good luck.