Cheque Bounce

I had booked a flat in TGS constructions last year which was a pre-lauch project. After 9 months of waiting for some progress, I finally decided to cancel my booking. At the time of cancellation they took all the original documents and handed me 4 post dated cheques of equal amount. They said without submitting the originals they will not be able to process the cancellation. Hence, on good faith I gave them the originals and took the cheques. After 3 months, when I presented the first cheque on the due date it was returned due to insufficient balance. I can issue them a legal notice but what are the chances that they will return my money? I spoke to 5-8 people who are also cheated by the same builder and none of them went the legal way. Some say it will take years to get the money and these cheaters will come out of the loopholes in our law. They may not accept the legal notice I send or I will have to suffer more harassment if I go it legally. Please help me with your advise, is there any way they can get away with cheating innocent people like us? Why so many people think that going the legal way will only cause harassment and the real culprit will enjoy with our money. I can file a criminal case if the builder doesn't reply my notice. But what are the chances that justice will be served soon. What pre-caution I can take? They also have a legal team, what option they have for not returning me?