Harassment to repay

I'm working as a human resource consultant. My job involves placing the students or unemployed in firms and we do charge certain amount as service charge. I have placed 3 people who were references of one of my friends and charged them. They worked in the company for more than 6 months and started claiming that we didn't like the organization way of functioning and resigned. From past 3 months they started harassing me to refund the charges started calling numerous times and keep on pinging on WhatsApp. Since they are financially well and have contacts with some politicians, these people started to threaten me . They reached out to my wife and told her that we are extremely connected and well off we will send goons if not paid or respond to the calls. Even they forcifully took cheques which were signed by me as a form of security till i repay and tried to bounce the cheque on the very next day. however as i already know the intention of them i informed the branch manager not to process any cheques from my account. this reached to extreme levels on 30th of april as they barged into my apartment and started threatning me for money. they harressed me for 5 hours and even asking for time to repay they didn't accept. what should I do?