Employer sent a incorrect notice

Hi Sir, I joined a Financial advisory company in indore (Market magnify Global research Pvt ltd), they asked me to sign a bond for 6 months, for which they asked me to submit a cheque of 15000/- without putting any date on it. I submitted all the documents and the cheque. They said this cheque is for security purpose in case if i leave the job earlier than 6 months. But i left the job after 10 days, where i signed there bond which was not on a legal stamp, it was just there official paper (but i have dont have any copy of that, but I have offer letter). I left the job without intimating the HR and they did call me but i never responded, and they sent a message that legal action will be taken. After leaving the job I stopped the cheque by calling my bank. after some days I received a letter (notice) from a lawyer, which says that I have taken money from the company for personal use and for repayment of that amount I have given the post dated cheque. They mentioned If i dont pay the amount of 15000, legal action will be taken against me as per the act of 138. which is totally incorrect. I dont think that there is such law where you can bound a person to a company and this is a false notice because I have not taken any money from them. what I can do? Can i file harassment case in this situation? Please advice..