I’m going to take a stab at answering this… It MIGHT be that you ran out of THB on the phone and need to refill. They are relentless about letting you know over and over and over, especially if you happened to go over the usage amoung on your GPRS…. So, they’ll debit your SMS card and pull the cash out when you top up your phone with some THB. Just a guess. Otherwise, no idea.