Recovery Letter - Outstanding amount payment demand

HI Sir, Can you please advise me on the below query/concern I joined DXC on 07-Jan-2021 and submitted resignation on 12-Jan-2021 due to family responsibilities and my father health issue. Management has given last working day is 19-Jan-2021 and they accepted resignation and pushed me to termination and kept in 'No rehire' to the company status. I suppose to serve 30 days of notice period but i served for 12 days. as per company policies the total payable amount is 74,000 rs/-. They recovered 40,000 rs/- from the salary which i will get for served days(12 days). the outstanding amount is 34,000, now the HR is demanding for the rest amount from me and other wise they will go legally they are telling. I am not expecting any experience/reliving documents from the company as they kept me in 'No rehire' status(in their database) and they terminated my employment instead of accept and relieve. I am requesting you to please suggest/advise me how to respond to the DXC HR as i am financially