Brian: Normally you would be correct. But the computer showing they never entered Mexico is immigration and the TIP is issued by SAT(aduana). There is next to zero communication between the 2 departments. It is my understanding that Aduana needs the vehicle to be present at the border for A permit cancellation. They need to verify VIN #'s and actually take a picture. Otherwise you must go through the mail process to Mexico city. I hinted to one of the aduaneros that maybe he could find a way to cancel my permit without the vehicle being present. He replied: Impossible!
Moisheh