Hi
1) The agreement will expire on 19 May as per terms of contract.
2) However as per Contract Act, you will need to issue notice(by registered post with acknowledgment due) to the prospective buyer asking him to fulfill his part of contract within next 10 -15 days from date of notice by
a) Pay up the entire sale consideration
and
b) come forward to execute the sale deed in his favour
and
c) Take possession of the flat
3) Please note that under contract act, you will need to ensure that you are able to demonstrate that the prospective buyer has NOT come forward to fulfill his part of contract and serving of notice is the only way to demonstrate that the prospective buyer was not willing to come forward to fulfill his part of contract.
4) If you have no previous knowledge of the prospective buyer or his antecedents, you should also file a Caveat petition in the court having pecuniary jurisdiction over the property, so as to ensure that the prospective buyer does not create legal trouble to you and your property.
5) With reference to Forfeiture of amount, even if there is no mention of the return of advance monies, courts will permit you to retain only up to 10% of advance monies received by you unless and until you can demonstrate to the court that you have suffered losses to the extent of advance monies on account of failed transaction.
Hope this information is useful.