Possession delay, clients demanding amount and flat.

A local advocate can provide immediate and practical remedy after studying the agreement signed in between the purchaser and builder.  Record the nuisance created by the purchaser with the help of unsocial elements in a video when he visits the next time and issue a notice reminding of the terms and conditions and your rightful conduct for compensating for the delay and ask him to proceed legally instead of creating nuisance at the workplace with help of outsiders.

Vague, confusing and conflicting facts have been posted by you.

You have admitted amount paid in cash and doubting paying capacity of the flat, which one of these statement is true ?

Who have granted stay and what is the reason for "stay" of possession ? 

What is the opinion and advise of your lawyer, who is well aware about the facts and circumstances of the case, an able, competent and intelligent enough to advise, guide and proceed.