Helped friend to get job now he is threatening to file cheating case

I had taught an IT course to a guy who came to through a common friend's reference and helped him in getting the job ,resume preparation etc.I worked hard day and night for the money I have taken and don justice for it. I have charge 30k from him. He has never concentrated on the course and always use to say that he is exhausted and finally after joining the job , right on the second day he has left the job and taken laptop to his home town and sent it back via courier along with lettter about his unwillinges to continue. Basically as he did not have stuff, he was incompetent and did not have interest and guts to work.He started blaming me that the company is a fake company and started demanding money back. He is threatening me that he will file a cheating case on my friend and me in his home town if the amount is not returned. He is blackmailing with the only point that interview was taken by me.He doesn't have any written proofs of the money transaction and hence he is recording all