I would have appreciated an update of the situation regarding my car - but as I have some mixed-up news, I will try to comment.
I would think it easier to disconnect the water pump out-let & run it for a while to see if the pump is in fact working & or leaking?
The belt being mangled/broken can only be an installation error, but it is not so much money to argue about.
I understand that the valve checking will prove the system, but not getting any information it is difficult for me to keep up to date.
Look forward to hearing from you - can write in Thai & I can translate no problem.
thanks,