International calling does not work

This was a very frustrating experience. Before leaving for Mexico, I chatted with an agent who set up my phone with a global travel pass, and my wife's phone for pay as you go. When we arrived in Mexico I realized that I could not call my wife, and she could not call me. We would here a Spanish recording and then the call would be dropped. Interestingly, I could call other members of my family, also in Mexico. I had two long chats with agents about this problem. In the first chat I was transferred to three different departments before the chat was dropped. In the second chat the agent said there was a different international roaming for Mexico and they turned it on, but after resetting system network on both phones as per instructions, we still had the same problem. Subsequently I had two voice calls with agents. In the first call, the agent said calls to Mexico and Canada were "turned off", and that she had fixed it and I should test it with a call to my wife. This meant I had to hang up with the agent and try calling, but it still did not work, always we heard the Spanish recording and the connection dropped. The problem was never solved, we are flying home tomorrow. I will recommend Xfinity mobile to others for US only, I will definitely warn all my acquaintances to NEVER TRUST XFINITY MOBILE FOR INTERNATIONAL CALLING.