My name is ***** ***** I am a NSW Solicitor. Thank you for your question, and will do my best to assist you with your question. Please understand this is not legal advise but a guide to assist you.
If he has lied about you, and you replies with the truth he is the one that can be sued for defamation. You have a valid defence.
No they will not take your passport it is a civil matter not a criminal matter.
He has to sue for compensation and to get anything he has to prove they were lies and they affected him in a negative way. You have a valid defence of truth.
I hope this makes sense and is of assistance. If there is nothing further
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