Welcome to the community!
Since your issue is regarding your account, you would need to contact customer service so they can access your account to look into your situation. Alternatively, you might consider sending @FidoSolutions a PM. Once they verify some information, they'll also be able to access your account.
With regards to the roaming email you received, you should note that receiving that email (and/or text message) does not necessarily mean that you've incurred the roaming charge. The email informs you that should you use your services (ie make or receive calls, send text messages, or use data), that usage would incur the roaming charge. Since you've left Canada, you might also consider removing the Fido SIM(s) from your device(s). If the SIM is not present in the device, there would be no possibility for any usage to occur using the SIM.
Hope this helps 😀