Did you change the APN settings to Koodos APN settings? If not try that, just Google Koodo APN settings and a bunch of posts will come up with them listed. Create a new APN and apply those settings save it and erase any other carriers APN you have listed.
When you first register with Koodo, they will send you the configuration, make sure to install them, if you didn't then send a message to receive the configuration again, if that was the problem. If not, make sure that the data is turned on.