1) how was money paid ? by cash or cheque?

2) you can rely upon receipt issued by him .

3) the builder cannot object to admissibility as it was his duty to affix revenue stamp on the receipt

4)you can also file complaint of cheating , criminal breach of trust against builder

5) you can move consumer forum against builder for deficiency in service and seek orders to direct him to deliver the stall booked by you for earning your livelihood

do declare payment amount of rs 25000 to builder in your income tax returns filed by you

money recipt is valid document to establish prima facei case. court will admit your case. it is not mandatory that money receipt should be registered but it should be signed. this receipt shows that money is transferred for discharge of a liability.

you should file either civil suit or file case before consumer forum.

Yes, definitely, the money receipt without revenue stamp is valid. You file a case in Consumer court.

In the absence of sale agreement, you cannot file a suit for specific performance of contract, but you can file a suit for recovery of money.

If your lawyer can draft a notice instructing him to perform his part of contract and register the property within the stipulated time after taking the balance of sale consideration amount on the basis of oral sale agreement, you may proceed with the enforcement of the sale agreement seeking to direct him to execute a registered sale deed in your favor through court of law.

The payment made was by cash.

This can be mentioned in the notice as well as the plaint of the suit. This is very much valid if you can gather anyone as a witness to this transaction.

The receipt does not bear a revenue stamp. If he is not signing the agreement then issue a legal notice to demand the refund of the money. The receipt is valid if it bears the seal and signature of builder,