Resignation accepted verbally and the notice period expired. But did not respond to the mail

Dear Sir/Madam I am going through something and I need clarity on this to understand the situation. I had a family health emergency and hence spoke to my reporting manager. They agreed to accept that situation and completed the handover procedure. Initially I sent the leave request to attend the emergency then as I was not able to attend to work, I put in resignation stating the reasons and the situations and sent the mail to the head copying the reporting manager, HR and few others. But no one responded to the mail. I called the reporting manager and they told to come directly and handover the laptop and collect my relieving orders. The notice period which I am bound to serve has expired now. Still they didn't respond to my resignation email and now after that period as I came to complete final processes, the head is holding my relieving order saying I have not served the notice period. I didn't receive the salary from the day I sent my leave request and not reported to the company. The handover processes are also complete with no pending work left. And the notice period which is 2 months from the date of resignation as they claim as per the contract has already expired.