How to issue legal notice? Can you give me any formate?
There is no specific format for this, you can draft the notice by yourself too, if you are not aware of the legal terms you can contact any lawyer of this forum who shall send the legal notice on your behalf to the builder. The details of all the lawyers are available in this website itself.
I am staying out of India. Can I send signed letter through email?
Sending it through email cannot be created as an evidence for a litigation that may arise in the later stage, hence it is advisable that you sent the notice through your lawyer.
I gave registered POA to my father, will it help?
On the basis of power agent, your father can send the notice on your behalf.
How long will take this process to get back money?
The time cannot be predicted.