Penalty due to delay in registry

Dear Sir/Madam I am a resident of Ace City Greater Noida West 201306. I took my possesion on 30th June 2019 and moved there. Builder promised me to do registry of my flat with few days but builder was not able to conduct registry process due to the hold from authority. As builder has to clear dues in authority due to this authority hold the registry process. Now in the month of March 2021 builder has cleared all dues and started the registry process. When builder inform us that they have started the registry process and we all had to pay the stamp fees , advocate fees etc. So we did the same and signed the draft registry documents. Now after this builder is asking the penalty for delaying the registry as only 6 months are the period to get the registry done. As per builder, I have to pay Rs. 50300/- in DD in favor of greater noida authority. But I am denying on this and ask builder to pay the penalty. In this builder holds my registry and not proceeding my documents.