How to get money from who barrow from me?

3years before my mom give 500000rs to her friend but she didn't take any documents from the person ..last 3 years she give only 40,000 rupees only (installed).recentlym my mom spoke to me about this problem..after I decide to meet the person.the person said I ll give the amount quickly..but I didn't believe the lady.so I made 100 rs documents and get signed from the person.later she give 2 blank cheque and 1 written cheque with amount of 5,00,000.and she ask me three months time ..so I wait for the period also..but she didn't give any single money from her pocket then I directly spoke to her husband .he said why u give this much money I can't believe that you give to my wife ..after she also accept that she barrow from us infront of her husband ..her husband said give one month time also ..but after one month period I met him..he said tomorrow I'm going to somewhere regarding my business day after tomorrow u can come and collect the money.but the same tomorrow he give petition against me and my mom..that we harassing her wife and take documents and cheque.later I explained everything to police station..the sub inspector said you can file case and put the cheque in to the bank ..but he stop the payment already..now what can I do .