Builder asking for penalty charges after giving possession at the time of registry
I am from Greater Noida. i booked a flot in greater noida in march 2019 with some amount. Its a ready to move in flat. Till July 2019 ,i was confused to buy this property or not. Later in August 2019 i got to builder and asked if they can remove these penalty charges and give me my original deal as promised,then I can continue.He agreed and provided me the updated "offer of possession" paper with removal of those charges and then I proceed with doing full payment and got the possession of the flat. Important thing to mention here:-
"I also got registry as an offer from builder"(Builder is responsible to get registry done)
I took my possesion on sep 2019 and moved there.Now builder has not done registry of my flat till feb 2020. In feb 2020 government rules changed and registry charges increased to 1% of flat value which was standard 20,000rs before. As now when I am asking for registry to get done, and asking them to pay this amount as I have already taken possession in sep2019. they should have get my registry done by now .
What they are doing now is that they are bringing those penalty charges(200000) into picture again and saying me to pay that if i want them to pay registration charges.
I want to know is it feasible that builder will bring the old penalty charges into picture after giving possession and even after 6 months i am living in that flat now.
As of now I have already signed the registry papers with builder and they have applied it to authority so that no late payment can be applied from builder side but in paying these charges all this drama is being played by builder .
can somebody please suggest how to proceed in this case?