Prestige Estates Projects Ltd - Complaint against Prestige Estates Projects Ltd- refund not given since 2012

I have booked a *.* BHK Apartment in Prestige Bellavista –Porur, Chennai (Flat No *****) and have paid advances of Rs. **,**,*** plus TDS Registration charges of Rs.***** also have been paid from ****.
I have not received any intimation of moving forward to complete the registration and handing over the Apartment. I have been receiving communication in terms of Magazine (Falcon News), Bday wishes and Anniversary wishes and Greeting cards and calender and email notifications, but no initimation with regards to my Apartment.
After repeated followups and mails and visits to the Office I get to know in Feb **** that the Apartment which I have booked has been sold to another customer.
I was not given any information or intimation about the same
So I requested for a full refund of the amount paid to the Builder (M/s Prestige Estates Projects Ltd)
As on date they have only been writing back in loops and as per the last mail they have written that the service tax will not be refunded as they have paid the same to the Govt.I got to know from my Legal Consultant that service tax cannot be charged twice for the same apartment and the refund of the same can only be claimed back by the builder since the amount has been paid by the builder.
As on date it is past * months since we raised a refund request and yet the refund is still not processed.
My monies of Rs. **,**,*** has been lying as credit with the builder since ****.
I hereby plead for justice to get back my refund of Rs.**,**,*** plus interest charges @ **% p.a for * years and compensation for the mental agony and pain which I have gone through by M/s Prestige Estates Projects Ltd.
I am hereby attaching the email communication for your reference.