did work for me. try it and see for yourself

I am not sure if I found the trigger of this issue.

The hotlink service was normal and connected to Singtel (no i do not have data roaming on or purchase any roaming package, just need phone to receive bank SMS etc).
After i purchased some voucher in apps and the credit balance fall to RM 9 and connection was lost.

I top up Rm5 and connection resume after short while. I believe need to have credit about RM10 (the cost of 1 day pass roaming) to maintain basic roaming.

hotlink WiFi calling workable oversea?

not working now maybe after they saw my post 

Bro, u are a life saver. I can confirm this work. Need credit >RM10 only roaming will work even though u only want to receive text only & not planning to use any data. I manage to get the screenshot. Here u go.