You may first check whether amicably by issuing notice to terminate with a clear intent has to be done. Thereafter steps can be taken to invoke legal proceedings, as against the developer and oust him from the project.
A.P.C.F &S.V. Act, Section 37(1)(a)
which reads as under:-
(1) In a suit for cancellation of a decree for money or other property having a money value, or other document which purports or operates to create, declare, assign, limit or extinguish, whether in present or in future, any right, title or interest in money, movable or immovable property, fee shall be computed on the value of the subject matter of the suit, and such value shall be deemed to be: (a) if the whole decree or other document is sought to be cancelled, the amount or value of the property for which the decree was passed or other document was
executed
of the ...for cancellation of the Development Agreement-cum-General Power of Attorney, which is otherwise payable under Section 37 (1) (a) in respect of suit of cancellation of other document which purports or... ... defendant who had offered to develop the property.
You can issue a legal notice to the developer seeking return of the document if it is just a notarised communicating the termination of the contract owing to his delay to start the project despite more than two years from the date of agreement.