The company has no real grounds to demand money from you.
You were sent on company work and you did that and came back.
Employee cannot be stopped from leaving after giving notice, just because company sent him/her abroad for work.
From facts you have mentioned the company is not on sound legal footing when they threaten you with legal action, trying to contact verification agency etc.
These acts will show company is harassing and not doing things legally.
Do not get worried but seek counsel of a good lawyer to whom you can show all the papers,dcouments etc and frame reply.
You were sent on company work and you did that and came back.
Employee cannot be stopped from leaving after giving notice, just because company sent him/her abroad for work.
From facts you have mentioned the company is not on sound legal footing when they threaten you with legal action, trying to contact verification agency etc.
These acts will show company is harassing and not doing things legally.
Do not get worried but seek counsel of a good lawyer to whom you can show all the papers,dcouments etc and frame reply.