When he did not call the next day, I phoned him. No reply. I looked at his app page. It was no longer there. None of my calls or messages ever received a reply. He totally vanished - and I had absolutely no idea why!
The boy never showed up at the airport. My friend tried to call him. No answer.
There are several reasons why communication breaks off, and with low class boys the main reasons is telephone broken/stolen/lost/no money for data.
With boys I want to see again, I try to establish several ways of communication (online dating, line, phone number, facebook), but keep in mind online dating and phone number are on the same mobile device, so if that is lost/stolen/broken, neither will work.
Facebook is better, because many use it from internet cafe as well, so they cannot lose/break the device. But they can forget their access data or get blocked from facebook.
The best is to know where a boy works or lives, or be in contact with his friends.
One low-class boy I really liked, I lost all contact with him in 2016 ?, but remembered he lived in Sukhumvit Soi xx (several hundred meter long) and was short of going there with a picture of him and asking people. (1) But then I remembered that he once called from a friend's phone, and found that number (2) and called the friend and could establish contact. We got together a few more times, but then I lost interest over his unreliability, difficulty to contact, money problems.
(1) Once in my room, we had a look at google street view and he showed me his place in Ayutthaya. In the course of sightseeing, I went there and asked people, but he had moved elsewhere and they didn't know where or have his phone number.
(2) Organization is important, I take calls from unknown number and save them, in this case "Top friend 23may2016"