1) file complaint against builder before consumer forum for deficiency in service

2) seek refund with interest .

3) you had cancelled booking as builder failed to deliver possession within stipulated period . in such a case 10%cancellation charges to be levied on buyer is unfair

4)also seek litigation costs and compensation for mental torture undergone by you

5) cases before consumer forum take around 2 years to be disposed of

6) most builders are facing financial constraints . hence delay in refund

In India it is most unwise to buy an under construction property as the builders are might corrupt and dishonest who either flee after taking money or just go to sleep for 3-5 years and wait for the raw material cost to escalate so that they may extract more from the buyer. Be that as it may, if there is no clause in the agreement which gives to the builder the latitude to refund the amount only on the resale of the flat, he is bound to refund it on demand from the buyer. So you should serve a lawyer's notice to him to refund the amount, and if he does not do then sue him for recovery of the refundable amount with compensation in the court.

local lawyer can guide you as time to be taken for disposal of complaint before state commission

It has to be filed in State Commission where it may take around a year

The cancellation o booking for the valid reasons from yor side is yor right and the provisions for the same has been properly made in the sale agreement itself.

Thus the builder cannot deny or delay the the refund once you have communicated your decision to cancel the booking in writing and the same has been acknowledged by the builder.

If yo find inordinate delay ie., beyond the stipulated time as mentioned in the sale agreement, you may issue a legal notice to the builder to hasten the demand made by you or to pay penal interest for the period of delay corresponding to the interest you are obliged to pay towards the housing loan.

If the builder is still not responding or not complying with the demand made, you my drag him to the consumer forum seeking relief ad also compensation for the mental stress he caused.

However I have one query...

How long does it take on an average for the consumer forum to give its verdict considering the refund amount is between 20L-50L and will come under the State Authority?

For me time is the essence..

A case before consumer forum will ordinarily take a year or little more than that depending on various factors, namely the behavior of both side advocates in the conduct of proceedings, court holidays, judge's leave, member's non-availability etc.

The delay in disposal of consumer case cannot be avoided and cannot be hastened to meet our requirements.