Welcome to the community!
What exactly is happening? Are you trying to port your number over to Fido? If so you just need to contact Fido's customer service and give them the info from your old carrier and they will start the porting process, you will need to keep the number you are porting active. You should get a text asking to confirm the port you just need to agree.
If you are porting the number away from Fido then you just need to contact the new provider's customer service and they will start the porting process and again you will receive a text asking to confirm.
If you did not request to have your number ported then someone might be trying to steal your number for nefarious reasons, in this case, don't accept the port request, change your account password and I would also suggest you change your banking info.
Although this Post is quite old, I'd like to add a little update since I came across it
Local number portability (LNP) enables you to keep your current phone number when transferring your wireless or landline service to another wireless or landline carrier. Once you ask to transfer a telephone number, a request is sent to your former carrier which initiates the process in order to complete your number transfer.
You can also find more information at this address : http://www.fido.ca/web/content/account/lnp?lang=en
I hope this helps.