Welcome to the community!
Sorry to hear you've received that unexpectedly high bill amount. However, you should note that International calls are not necessarily free. Fido does have a 1500 International Minute add-on. However, those minutes are only for the long-distance (LD) portion of calls. All calls are charged airtime and LD, if applicable. If your plan has a limited number of included airtime minutes (ie 500 Canada-wide minutes), any additional usage would be considered overage airtime and charged accordingly. For example, if your plan only includes 500 airtime minutes and you made 600 minutes of International calls (assuming to one of the included Countries), you would incur charges for an additional 100 airtime minutes.
Does your plan have a limited number of included minutes or does it include unlimited airtime minutes?
Also, as alluded to above, those International minutes are only to certain countries (see 1500 International add-on). Were your calls to one of the included Countries?
I understand this is a difficult time and this situation makes receiving such a bill even more distressing. If you're unable to make full payment on the bill, you might consider arranging a payment schedule. To make an arrangement, you'll need to contact the credit operations team. It should be mentioned that a payment arrangement might not be available in all situations.
Hope this helps 😀