Delay in position of shop and sold land of shop to other builder

Respected sir This is my problem my dad had booked shop in 2002 in boavali mumbai and paid a token amount of Rs. 1,50,000/- to the builder in 2002. We were promised that we will get the position of a shop in 2006. But builder has died in an accident and now his son is handling his business and he sold that land to another builder. Now he(builders son) is telling that he cant give shop and not talking to us about refund of money. Can anyone help me. my family cant hier lawyer due to financial condition what should i do now.