Have you connected your Bluetooth? Make sure you do.
If it still doesn't work, factory reset your vehicle's infotainment system, then try again.
If it still doesn't transfer contacts, try a different iPhone and see if it transfer contacts - this will rule out any problem at the vehicle's end.
If the other iPhone transfers the contacts, then you should factory reset your iPhone and then try Bluetooth+CarPlay.
If the other iPhone has same problem then there might be a software bug in your vehicle's infotainment.
