Tata Docomo — no network access even after activating international roaming

I am in canada for a leisure visit and wanted to make a paytm transaction which has docomo phone number. But i am not getting any otp message for the same. I have been in call with the customer support and they asked me to activate international roaming, which i did but my problem still exists. I called the customer support and they keep repeating to manually add the network operator but i keep getting the error "cannot connect to the network. Try again later". Please look into this issue as i am unable to make any payments. The complaint id is : [protected]