So, I am stuck in Thailand and my Metfone SIM card is not roaming. This used to work, but this trip I get absolutely nothing. Yes, I did pay for it. I checked before I left and the SMS came back saying roaming was subscribed.

When I check to see available networks, (by going to Settings->More->Cellular Networks->Network Operators in Android 5.1.1) there are none available. The same phone when I insert a local Thai SIM card shows about 20. The SIM card is just fine. There were no issues with it when I left the airport, and I'm certain it will work just fine when I return.

The problem seems to be some kind of issue in Metfone's network that won't authenticate the SIM for roaming. I tried emailing Metfone to the address on their website, but not surprisingly I get no response.

Does anyone have a way to contact Metfone that doesn't require paying expensive charges to call Cambodia from Thailand? Or can anyone suggest something I can try to make this work?

Sorry about not thanking you.

I did finally get an answer from Metfone who had no useful ideas and suggested I stop by a shop when I get back so they can look at it. The answer doesn't come as a surprise.