i know a friend had the same problem and his wife was so smart even when she signed all the legal papers to give full custody to the father ( Australian ) when they arrive to Thailand with thier children ,, the frist thing she did is she went to the court and she block her children passport ( 2 girls and a boy with Australian passport ) and now they still fighting for the custody in Bangkok 💔💔
my friend did it with cooking institute but he didn't check if it's approved by MOE and he gat the visa by submitting the course papers and the payment