Non Acceptance of Resignation

Do as per your Appointment Letter states. If it states that you need to serve one month notice, do it accordingly.

Not not that, it must also state that you will be there n lieu of one months salary if you quit without notice. If it is not there, ask your new employer if you can  abscond. If they say it is fine, then leave the company. Or else the new employer will give you permission to serve notice period.

Ok. Sometimes, the organisation likes your work and could have recommended you to stay with them. I don’t see anything wrong. At the same time, when you are serving your notice period, there is no legal enforceability that you have to stay back once you have notified through an email.