sorry for that,
1. before leaving the country have you call the HOTLINE to check if the ROAMING of the account is active?
2. or is there any unpaid balance on the account?
3. you need to talk via chat (since you are in Canada) to activate the ROAMING, try to ask if the SIM that you are using is active on the webtools that they're using (for alignment), if there was no problem on the account there might a possibility that there was a problem on the signal of the said country.
4. have you try to check the network operator of the phone that you using? if it is not automatically receive a signal you have to manually select the roaming operator.
5. try also to check if the phone is not be call diverted
6. check the SMS center number, it should be +637301000