every time i leave the car i get a configuration message 500 plus to date
bt then send a message saying i'm using a new phone
do you have iphone on IOS14?
You do normally get them when changing your sim from one device to another. I'm guessing that for whatever reason, the connection the phone is making to your car is making the sim think you've put it into a new device altogether.
Not sure if there's any way to stop that really other than blocking the number the message comes from.
Take the SIM card out and clean it with a lint free duster.
If that doesn’t work you might need a replacement SIM card.