Company Rejecting to do buyout

Hi, I am working in a small IT company in Hyderabad. Initially joined as a product analyst and recently changed my role to business analyst and sent me to another city to work at client's location. Due to some unfortunate circumstances, my mother fell sick and I badly want to be back to Hyderabad and be with her. So I resigned from my services informing HR and my reporting manager stating the reason and also informed them that I can serve one month of notice and will buy out the second month (As per organisation norms 2 months is the notice period). After 23 days of me sending the resignation letter and I will be completing my one month notice in a week, now got a mail from reporting manager stating that they cannot relieve me without 2nd month notice period. I also called HR team 10 days ago to check the status of the my resignation. They informed me that my manager accepted it and I will soon receive a mail from him which I never got. Irrespective of responding to my email after 23 days, they are now saying that they cannot relieve me in one month. I have gone through my HR policies which clearly states that 2 months will be the notice period and remaining notice period shall be paid by employees. Please suggest me on how to proceed further on this. Regards, Ram