Sorry that your having phone problems dazza - there are numerous possibilities including:-
Good Options
1) Govenment shutting down mobile networks as all contracts are illegal - read here:
Bangkok Post: Top Stories
2) She had her phone lost or stolen. (Bit bad cos you will have to pay for a new one).
3) Shes run out of money and sold her phone.
4) Shes forgot to charge her phone.
Bad Options (hopefully not any of these)
5) Shes had an accident.
6) Shes got a new boyfriend and shes otherwise occupied for now. (This one will resume normal phone service once new b.f has left town).
7) Her Thai boyfriend has sold her phone.
As you dont say where she is etc - its hard for us non-psychic BM's to tell you. If disruption in service continues or you dont get an email reply - consult Mav at HHplc - top investigations guarenteed
.