Car Insurance

I am not an expert but clarification is required on your status.

Still the questions, first are you living permanently in Mexico? If so, then you have to comply with the INM rules visa and residency wise. Also, have to comply with the mexican Aduana rules in regards to the importation of vehicule (no more vehicule plated outside Mexico except with a tourist visa max 180 days).

If you are on a tourist visa (180 days max), then I presume you still have a residence in the States so you should be able to keep american car insurance.

Buena suerte, GyC.

Gracias, GyC - I am here on a tourist visa as I'm not sure how long I'm staying. I don't, however, have a residence in the US, just a mailing address. Should that be sufficient for car insurance? It seems to be fine with Medicare.

No idea, since I am Canadian, sure some one will be able to awnser that. Good luck again, GyC.

Trying to equate government and a private insurance company may be futile.
Did Geico tell you why it cancelled?
Your worst case solution is to buy temporary insurance for the US at the border for the days you plan to be in the US.

I would contact Geico and find out what the problem is. Most of their activity is on line. Perhaps you have a friend's address that you can use. They don't insure in Mexico which is the likely problem, except for your having a US license, and address. Just being a visitor should allow you to just have Geico and drive back and forth as long as you stick to the area you are in. Only they have the answers.

I had Mexican insurance and Geico until I became permanent because I was back and forth a lot, and live in southern Mexico.Of course Mexico is changing rules again so you might want to check that also.
As we say here , never a dull moment.