Recqured Suggestion

I am a Midal class person and I wanted to build a Granight stone florring work at home . As I don't know anyone who is in the field ,I called some person like friends , relative, they are circulate my mobile number. after one days a call come my phone. the person talks as a Granight tiles contractor. this person name amit . Initially he was very polite and so thought he is nice person ... so I entered the contract with him. Initialy I paid him Rs 8000 (by Cash) and he brought the structural materials next day and instructed his guys as how to the work. The work went well for a Three days. after Three days Amit demand 6000 rs, my father give cash amount. next days worker not come. at evening Amit called me, machin not work give me 2000 rs, i told go home and take money . and subsequently all went wrong (meaning no work) as he kept giving excuses. in Two & Three days they are cut lot of stone. my lot of material dimaged by Amit & Worker. In this period they complete half room. their cell is off all time. Some times it rings but no response. as per my calculation Approxmat 14000 Rs to 16000 Rs stone distroyed. after search out i found some Contractor creat a whatasp group, they are circulate Mobile Number in this group. they are defaulter contractor , they worke two & three days one site , take money & sutdown sit work. As a true citizen of India I want them to get punished. I would appreciate if you could suggest me to take forward to curb such criminal. Besides your suggestion will help me to make these guys not to cheat anyone in their life.