1. Personally meet the builder and get information about the date by which time he refunds the amount to you.
2. When he specifies the date, ask him to give a cheque for the amount, to be encashed by you on the specific date.
3. On the specific date, present the cheque to the bank, and if you can encash it, then your problem will be solved.
4. If the cheque bounces, send a legal notice to the builder U/s. 138 of Negotiable Instruments Act to pay your due amount within 30 days from the day the information from the bank is received to the effect.
5. If the drawer fails to refund your amount within 15 days from the date of receiving the legal notice, then cause of action arises and you can proceed legally U/s.138 of N.I.Act.