Here's what I do:
I make a digital and a paper copy of emergency phone numbers including banks that handle my ATM card and my credit cards. I also include key tel numbers of my siblings, my doctor, the air carriers I am travelling on, and my medical insurance carrier. The digital copy I store on my phone in a "Notes" file. The paper copy goes into a plastic pouch with my other documents (I am old and neanderthal, so I still carry a paper copy of reservations for my lodging and my rail/air travel and a picture of my passport home page).
I also use Skype credit to call home and it's available in an emergency. In the US, you buy in $10. increments. Then I can call both mobile and landline numbers back home whenever I have a decent internet connection. Call cost is very, very low. I also use Skype occasionally to make reservations when I am calling from the US to Europe. Others on this forum have recommended other Skype-like calling applications like Viper.
Of course, with a good internet connection, you can call from one Apple phone to another for free using Facetime, but calling a landline, such as your bank in the case of a lost or stolen credit card, is not possible with Facetime or Whatapp.