Samiah Builder — Flat booking

To the authorities
I have booked a 1 bhk flat in gulmohar society in rudrapur udham singh nagar in 2012 and i have already completed 90% payment (5 lakhs) and they promised to give flat within 6 months of allotment but after 8 yrs they haven't even started and their response is so poor that when i call to thier office they r not picking up phone now, now i want my refund with intrest rate, please help me. I will provide all related documents to the respected person if any actions will be taken by authorities. Please mail at me [protected]@gmail.com if anyone o[censored] have same issue as i have, so that together we can file case.
Thank you