I sent my resignation letter to my manager and hr today. The notice period is of 1 month and i am working in an MNC. The issue that has arisen is that my manager is refusing to letting me leave before 31st Dec and has been emotionally blackmailing me and calling my decision selfish. I have had a cordial relationship with my manager till now so to say I didn't imagine our interaction going this way would be an understatement. Being the dumbass i am, i even told him which company i will be joining. Now, he has even vaguely threatened about contacting the HR from that company.
Going forward, what are my options? Can he refuse to accept my resignation? And can he affect my chances in the other company? Please help as i have been losing my mind over this all day today and could use some wise counsel.