Supertech — eco village 1 flat is not ready even after 1 year of ndc

I have made full payment for my flat in supertech eco village b11-108 and received no dues certificate on 7 augest 2019. Ever since i have been visiting the site to get update on the status of work completion of the flat or talk on phone with the concerned officials who are handling the same. Every single time i get the same response that this will be ready be end of this month. Need to understand why there is so much delay and i would like to have the interest cost reimbursed to me at the same rate of interest as they have charged from me for delayed payments.