Dear Concerned,
The Assured Return Schemes are not approved by any law - and hence people enter into such schemes at their own risks, however in such a case your interest is covered by Consumer Laws and Criminal laws as well.
Lets look at Litigation - You can choose to file consumer case and ask for 100% refund of your money - however it would take many years for this to be settled.
Criminal complaint on the basis of cheating and harassment can be filed and this may lead to settlement as well - however police may not register the complaint stating civil nature of the case.
At this point it is suggested to try speaking with the competent persons at the builders office for status of assured return , if they do not reply or entertain , FINELY GO THROUGH the terms of cancellation of the Builder buyer Agreement and send them an email for cancellation of your booking and asking for refund of money , also send them a speed post of the same followed by sending them a legal notice.
You should be able to get your money within 8-10 months if the developer is courteous enough to refund the money on cancellation.
Best of Luck.