Welcome to TPG Community!
We recommend having a read of this community article, which can help you with this query:
How to activate International Roaming
We have located an account using your community details, but we can see 2 active mobile numbers. Can you PM us the mobile service number you're referring to?
To send a PM, please refer to this link: How do I private message (PM) in the community - TPG Community
Thanks for sending us additional details. Based on the records, roaming is already active in this mobile way back in 2017. (Possible the roaming was not being switched it off)
Please try to manually select a foreign network on the phone.
Step 1: Go to settings > Wireless and networks > More networks / Mobile networks > Network operators (The phone will automatically search for any available networks overseas)
Step 2: Once it listed down the available networks, click any provider that appears there.
Step 3: Restart the phone.
Let us know how it will go. Cheers!