You need to manually enter the APN (or network) info. Since its Bell branded, it only has the Bell network info built-in.
Go to Settings>Wireless & networks>Mobile networks>Access Point Names
Then create a new APN and enter the following info:
Proxy: leave blank
Port: leave blank
Server: leave blank
MMS Proxy: wireless.cingular.com
MMS Port: 80
APN Type: leave blank
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Phone: HTC One X (AT&T version) Rooted, Bootloader Unlocked, S-Off
Tablet: Samsung Galaxy Note 8 (WiFi only) Rooted