Still having the same issue myself. I've had my SIM replaced, I've had 2 or 3 software updates (the last 2 were on May 27 and June 15), and still no go. This past Friday, my wife and her mom and I were driving down to Ensenada for a family event. After we crossed the border, my phone lost service, but both of theirs worked. I called Verizon from my wife's phone, and spent almost the entire 2-hour drive on the phone with them. They were not able to resolve my issue and opened up a ticket with engineering.
About 2 hours later, on a whim, I went into my phone's settings and tried to manually connect to TELCEL. Guess what? It connected! And it stayed connected for the remaining time we were there.
We came back home late Friday night (really, early Saturday morning). Today (Sunday), I tried calling a number in Mexico. "Number not valid" on my screen. Then I tried calling *611. Same message. This is the other thing that happens: Every time my phone doesn't work in Mexico, it also stops being able to call international or "special" numbers when I'm back in the States. A call to Verizon fixed that issue (they re-provisioned my international/roaming capabilities -- I think they've done that before, but I can't remember). But I don't know if it fixed the Mexico issue or not. We don't go there regularly, so it's hard to say when I can test it again. Bottom line is, I need my phone to work outside of the US, and if it continues to be a problem, then I am going to pressure Customer Care to replace my phone with a different model, such as an S20 or maybe a different brand.
