Are your APN settings set to Koodo under mobile networks in your phones settings?
Make sure data is enabled in settings under data usage.
Did you check self serve to see if you have a data block on the account since you've made the change to the new plan?
Still experiencing issue? Still not able to access data? If the APN is correct, you probable have a data block on your account. In this case you need to contact us since it is no longer possible to remove it from the Self-Serve.