I had the same problem. Twice. Just got back yesterday. I have an iPhone 13 pro and I spent well over three hours of my vacation on hold or speaking to customer servie. Ended up speaking to a guy named Steve from tier 3 international support, who said "he'd make sure it was fixed". Never did.
So frustrating. All the wasted time. Steve said it looked like the mexican cell companies were blocking my numbers (wife;s also) from roaming.
I believe I'm done with Verizon and their lack of follow-through regarding support. My employer uses T-Mobile and have never had a problem anywhere, with great tech support when needed.
December of 21 is when I first reported the issue. Called right before going again last week and a rep told me "it will work, guarneteed". lol. 7 days today since wasted 3 hours being promised it would work, and someone would get back to me.
I did get a text yesterday saying they were unable to reach me. They apparently didn't comprehend the fact that I had NO cellular connectivity.