Issues with WiFi calling while abroad

I purchased Mint last month on the $180/year promo. I'm kind of regretting it now since we set Wi-Fi calling up before my kid went to Japan for the next few months. Texting only seems to be working sporadically, and Facetime/WiFi calling hasn't seemed to work either. We've been getting by with WhatsApp, quite honestly it works well, but I kind of feel like I should've just parked their number for the time being since Mint doesn't allow pausing service. Any tips and tricks? One other note, we are using a second eSIM for data while they're there, and I had activated a few days of Mint international data and things worked until that ran out.