RTO India — RC book not delivered by RTO

I have purchased Hyundai Venue (TS-07-HW-8215) on 29th oct 2021 registration date but still i have not received my rc book, when i went first time to Kondapur rto they given post office tracking number which is ems traking then went to kothaguda post office so they said please contact rto as we returned your RC book then again went to rto they said please visit kothaguda post office and saying we dont have your rc book, you have to contact post office only or else apply for duplicate rc book and for duplicate rc book all the documents required which is fir copy, valid insurance, address proof etc but why should i apply for duplicate rc book for which i have not received my original rc book, request you to please look into this matter and do the needful asap.