Hello Civilization,
Welcome to the community!
Sorry to hear you've experienced that unexpected usage. However, I'm not sure how any of what you note is due to Fido.
While the link you posted doesn't appear to work, I think I was able to find the link here. Is that the correct link? I understand you might not have knowingly used the data, however, your device with Chrome installed did. No internet provider can discern whether the data used was intentional or due to background usage. It would all be considered usage so they were telling you the truth that the data was in fact used. It would be the same with any provider.
In addition, you seem upset that you had to search for what was wrong on your own. Fido provides the service. They may be able to offer assistance with some matters, but they can't be expected to know how people use their devices. All they can know is how much data is used. It is the customers' responsibility to monitor their own and their devices' usage. Sometimes, that includes having to search for your own answers. This community is a great source of information. However, there are times when we have to search elsewhere.
While people can't seem to live without their smartphones, that smartness can come at a cost. Having all that information at your fingertips means that many apps use background data to keep updated. If you haven't already, you might consider going through your apps disabling background data on those apps which you do not require frequent updating. On my device, only a select few apps have access to background data.
Hope this helps 😀
Cheers
