I received my bill today and it included long distance charges because my iPhone didn't do the call as a FaceTime audio but instead as a regular call. I had not had this happen before and there was no warning to tell me that this would be a long distance call for me to decide what to do about that. I tried explaning my situation to the customer service representative and they did not understand how it happened, it seemed that they are not aware of the phone's features.
Welcome to the community!
I'm sorry to hear about that awful surprise on your bill. Is it possible that Apple changed their Facetime interface such that making calls through the app is now different than it was before? Another community member noted a similar issue they referred to as a glitch (see here). It would be up to customers to know the how the apps work on their devices -- even if those apps may have changed how to access certain functions.
Unfortunately, if the calls are listed on your bill, your phone did make those International calls. I understand you did not intend on making those calls via the networks. However, they were connected via the networks. The long-distance calls were made using Fido's cellular services.
If the calls are on the system, they would be included on your bill. If you are unable to pay that full amount, you might consider contacting Fido's Credit Operations to make a payment arrangement.
I'm sorry if my reply seems harsh. I do understand how stressful this situation must be for you.
Hope this helps 😀