Hello and welcome to the Androidforums.
Do I understand correctly that you previously had both voice and data connection, and that now the phone is only capable of voice and SMS (texting)?
Apparently something has changed, but the first diagnostic would be to check the APN settings, as indicated in
Koodo Mobile - Non-Koodo Phone Data Setup although you can ignore the "Setting up Tethering" section, as the N4 is natively capable of tethering. Also, the MMS settings are on the same APN page you're editing.
Forgive me if you are already totally familiar with your new N4, but hopefully to save you a few minutes of discovery:
Settings->Data Usage .. More->Mobile Networks-> Access Point Names
and either create a new one or edit the one you're using according to the parameters in the link above, taking care to both save the edits (menu dots in upper right corner) and then to select the APN that you want to use.
Let us know please how that works for you. It's good to see your provider welcoming tethering, as that really makes life easier when one and friends are "on the road" with laptops, assuming unlimited data availability.
If you don't have unlimited data service, then it's a good way for them to get your money.