Consumer Redressal

1.5 years ago I entered into a MoU with a builder stating I pay 7L Rs and they give me 24% pa interest (Rs 14000 pm) for 14 months and then return the principal after 14 months. Builder only paid 2 months interest. 4 cheques bounced after that. And they have not paid a single penny of interest or principal after that. They kept delaying and asking to come after few weeks always. Finally on saturday they said they will not return my money. I have proof of cheque bounce. I also have all the unutilized post dated cheques which they asked me not to deposit. These have expired now. I also have email conversations and phone call recordings of their conversations. I want to get my hard earned money back. Suggest me what should I do.