Hello Lucille54,
Welcome to the community!
Sorry to hear you may have incurred unintended roaming charges. However, your statement is not necessarily correct. Had you actually received roaming charges or had you received the Welcome Abroad text notification? Merely receiving that Welcome Abroad message does not necessarily mean that your device had used services. I was able to confirm that merely receiving that message does not incur roaming fees (see here). However, if you did incur roaming charges, it's likely your device used other services when it connected to the foreign network.
The Fido Roam charges will only incur if your phone uses services -- make or receive a call, send a text message or use data abroad. While receiving SMS would not incur the roaming charge, it's worth mentioning that the data contained within MMS (incoming or outgoing) would be considered roaming data and charged accordingly. You should note that MMS are not solely restricted to pictures or video messages. Messages with subject headers or group messages etc are also considered MMS. It should also be noted that RCS messages are sent (and received) as data and not as text messages (SMS). Even if a received text message is SMS, if your device is configured to provide Delivery and/or Read receipts, those would be sent as SMS or data and considered roaming usage.
I understand you had disabled roaming data. It should be noted that disabling data and roaming data does not prevent roaming for calls and messages. In addition, it should also be noted that some phones might consider certain system data differently from user data and continue to allow the former usage despite data and roaming data settings disabled. For example, while disabling data and roaming data should prevent data usage on foreign networks, some mobile manufacturers (ie Apple) does seem to allow some data usage despite those settings disabled. And no, it doesn't seem to be a Fido issue. It happens with multiple providers as well (see here). That's why in order to prevent roaming charges, it is usually recommended to keep Airplane or Flight modes enabled for the duration of trips. Customers could manually enable Wifi when required.
With regards to Wifi-calling, it should be noted that while using Wifi for regular internet access will not incur Fido Roam charges, there seems to be some misunderstanding regarding the feature. 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).
Fido Roam is enabled by default on most current post-paid plans. If you did not wish to avail of the feature, you would have to opt-out of Fido Roam. In doing so, any usage would be on a pay-per-use basis. Those rates can be found here. Alternatively, if you did not wish to use any services, you could request to have roaming blocked on your account. However, you should note that a roaming block on your account may prevent Wifi-calling usage while abroad (see here). You would need to verify which option is applied to your account as some customers had assumed they requested a total roaming block only to find pay-per-use usage abroad (opt-out Fido Roam).
Yes, it is possible to have incurred roaming charges with data roaming off. In addition, it is also possible to have incurred roaming charges depending on Wifi-calling usage. However, it is entirely possible to not incur roaming charges with the proper settings and specified Wifi-calling usage. The mobile providers only know usage, not what settings may or may not have been enabled on a particuar device. Unfortunately, if unintended usage was logged on the system, that use would be considered roaming and charged accordingly.
You should note the forums are community-driven and not intended as a venue for customer services. If you wished to discuss your matter and/or opt-out of Fido Roam (or apply roaming block), 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
