Let's get to the numbers right away and please tell me your opinions or if you had a similar experience.
I have a prepaid TrueMove H, 2 baht / MB if NOT on a data plan (which is a lot I know, but it came with the particular SIM card I'm using).
I had a data package, it expired at exactly 12 midnight last night.
At 12:10 am I get their sms "remaining credit is 18.35 baht".
At 12:15 am another sms "your remaining balance is 1.23 baht".
What was my usage after 12:00 am:
* Line app (chat messages with one person, no voice messages, no video call, no photo downloading)
* Wechat (just running, no chatting, no messages, maybe Moments was updating?)
* No internet browser activity
* Auto sync off, background data off
* 0 voice calls
* 0 SMS
By way of comparison, similar usage in Shanghai (where telecoms send you SMS with your data usage every day) is 10-12 MB per 24 hours, not per minute or per hour.
At 12:40 am I went to the 711 next door and topped up 30 baht just so I have a balance and can see what's going on.
I go home, turn on the Wifi (maybe I left the data connection on at the same time), go to sleep an hour later, checking that data connection is off.
I wake up this morning, check my balance, 17 baht. Unless I was using my phone in my sleep, I have no idea where 13 baht went.
Now, the amounts are small, but if you multiply them by top up frequency and subscriber numbers, you can easily see what TrueMove may be thinking: "the beauty of data charges is that there is no way for a subscriber to know what and how much he/she is consuming".
I called their Customer Service line and after going thru the above and not getting any clearcut answers (surprise), I asked her to tell me exactly how many MB I consumed from 12:00 am to now. She said she can track it but have to refer to another dept and will call me back. I'll update when she calls back.
PS. I spent another 100 baht (before I got the data package) on data charges in 1-2 days, so this was a good opportunity to rant a little on a saturday afternoon. The real incovenience and problem is when you find you have no balance for any urgent calls or sms because of questionable data charges.