Hey there @Hotrodder,
Welcome to the Community 
- What Android phone model is being used?
- Are you unable to text one specific user on LTE or to all your Android contacts?
- Have you changed devices when making the switch from Rogers to Fido?
It's good to know that your SMS (regular text messages) do not require any data connection to be sent. That said, if you're trying to send an MMS (text message with pictures or videos) your mobile data will need to be enabled in order to send/receive them. Though this requires access to data, it's free of charge and won't use up your data since it's included in your plan, but the data connection is still required.
A simple test we can suggest is having the Android device send an SMS, then an MMS to the number associated with it. If that phone is able to successfully send and receive the messages, then everything is good to go. You'll then need to go over your phone's settings to find out why you need to be connected to 3G instead of LTE.
I would suggest to start by verifying the Android's APN settings, then depending on your phone model going to Settings > Connections/Mobile Networks > Network mode > Make sure that LTE is selected.
Hope this helps!
