Company did not accept resignation,now asking for notice period amount

I was working in a reputed company from last 3 months, i had health issues and I hadn't recieved a single rupee fron d date of joining, because of these 2 issues i applied for resignation, but manager told me to withdraw my resignation saying that he will put me for another process and also will be gtng my salary by month end, so i tuk it back. By mnth end both the things didn't happen wich dey assured me, so again i applied for resignation and dey didnt accept it, so i didnt have any other way , so i just left the job. Now i recieved a discharge notice saying that i have pay the notice period amount , wich I m not willin to, because i was ready to serve the notice period when i gave resignation but they didn't accept it, so how fair is it to send such notice that too without giving my salary, dey are asking me to pay, i dont know what to do, please help me with this. I haven't signed any bond