Questnet — gold coin not received

i had joined this mlm two months back and ahave not yet received the gold coin they promised...fortunately i had only given rs 10000 in advance to the dealer..mr deepak v nair working in infosys hyderabad ...the rest of the amount was given as post dated cheques which i cud fortunately stop as soon as i knew bout the scams...people like deepak and those under him are still tryin to make me pay up. i would like to know how i can legally approach against them.