This is not an immigration law question.
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This is only sort-of a US Immigration law question.
I suggest you hire a US licensed attorney in Thailand.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
This is not a US immigration question and I know nothing about why they took your passport, nevertheless I will take a shot at this and suggest that perhaps a US relative can contact the US Department of State in Washington DC and inquire? they have authority over all the US embassies. I would look for an email address on their website.
Due to the nature of this forum, I often do not have all the information required to provide legal advice. Accordingly, my responses on Avvo are intended as general and not legal advice.