Welcome to the community!
What phone do you have? Was it purchased from Fido? If not, have you verified whether it is compatible with the networks? You can verify the compatible bands/frequencies here.
Have you verified the phone is using the proper APN setting? You can verify those settings here.
Just to clarify, does your plan have data included?
Does your issue happen everywhere? Are there any area where you are able to use data?
Hope this helps 😀