Refund of registration money of flat

I booked a flat in a pre-launch project in ghaziabad. The registration amount of Rs six lakh was paid in november 2013 and was tentatively allotted flat. On july 2014, a demand cum service invoice was raised for an amount of Rs nine lakh and the payment for the Same was made in 15 days. what is a legal option for me get the refund of payment, as till date neither i have received an allotment letter nor any update on the project. I have written series of mail to builder and on their advice sent application for refund thru registered post too. Now, the concerned people are not even picking my phone. the registration form mentioned that ” for any reason whatsoever, if the company is not able to provide allotment for a period of 1 year from date of credit of application money then the company shall upon specific request of the applicant and completion of formalities shall refund the amount in full with simple interest @10% per annum with no further liability to pay any damages compensation in any form”. kindly advice. BUILDER OFFICE IS IN NEW DELHI, PROJECT IS IN GHAZIABAD. HOW N WHERE TO FILE CONSUMER CASE.