Is it possible to get a detailed hourly breakdown of data used the previous billing period? It shows I used over 7 GB in one day and as I usually don't go over 3GB in a month, it seems very strange. Just want to know what settings I need to keep an eye on so it doesn't happen again.
You can get your data usage breakdown from your detailed invoice, see here on how to save your detailed invoice.
Also, Fido provided your data usage per day and not by the hour.
Do you have an iPhone by any chance? iPhones are known to use rogue data in the background.
You can also make sure you do not have WiFi Assist/Download Booster enable.