Hello Kehass,
Welcome to the community!
Sorry to hear you've incurred unexpected roaming charges. I cannot speak as to what was previously discussed when you contacted customer service.
The Fido Roam charge incurs when your device uses Fido Services abroad. That is, the charge will incur when you make/receive calls, send text messages or your device uses data outside of Canada (see here). The mobile providers only know usage. If a device is using services when its settings are set not to use them, that's an issue with the device. The mobile providers have no access to a device's settings to know what settings are enabled/disabled.
I understand you may have disabled data and/or roaming data. However, you should note that disabling data and roaming data does not prevent roaming for voice and messaging. In addition, some manufacturers might allow some data usage to occur despite those settings (see here). It is generally recommended to enable Airplane and/or Flight modes to prevent unintended roaming usage. You could then manually enable Wifi when required. Had you enabled Airplane or Flight mode on your devices?
I understand many people still wish to use their devices with Wifi. Generally using Wifi for regular internet access will not incur Fido Roam charges. However, there seems to be some misunderstanding regarding Wifi-calling. I'm not sure how people have gotten the impression that Wifi-calling does not use the networks. However, that is not true. While the calls and messages do not transmit via cellular towers, they still use the networks via the internet gateway (see image here). The cellular towers and Wifi are merely alternate means of accessing the networks. Calls and messages would not be able to complete or get sent/received without the networks. As such, using Wifi-calling is technically using Fido services. However, they have allowed certain usage to be free from additional charges. All the messages and calls you receive (from anywhere in the world) will be taken from your plan's voice minutes and messaging limits. As well, all Wifi-calling messages and calls you make to a Canadian phone number while abroad won't incur long-distance or roaming charges (see link above).
I also understand this is a difficult time and receiving such a bill even more distressing. If you're unable to make full payment on the bill, you might consider trying to arrange a payment schedule. To make an arrangement, you'll need to contact the credit operations department. It should also be mentioned that any arrangement would be at the discretion of the credit operations team.
You should note that the forums are community-driven and not intended as a venue for customer services. If you wished to discuss your situation, you would need to contact customer service. In addition, they can also be contacted via Live Chat, Facebook, or Twitter. Those methods can be accessed via the contact page posted above.
Hope this helps 😀
Cheers
