What can I do if my friend is forcing me to invest some of my money in trading?

I am a stock market trader and my friend approached me to trade for him on profit sharing basis, We started a year back it was going well. we made around 50 lacs profit he has withdrawn it..later on we have made a loss of 50 lacs ..which means whatever profits made is gone and now it is 0. but they are asking me to put my money to trade for them. But i told them i will recover it or i am ready to give whatever profits taken from them. Now, he is saying that he will go to legal and file a cheating case. How can I come out of this issue.