Hello Muskaan-Mahendru,
Understanding the Difference Between Material Handover and Relieving Date
Handing over company material—in your case, the laptop—is different from the relieving date calculations, which sync with the last working day (LWD) of the employee. What would the concerned manager do if the employee informs very clearly that he/she would not be able to work from a certain date? Run after you? There may be some HR persons who may do that, but don't expect all to do it.
Importance of Discussing and Agreeing on the Last Working Day
I suggest being realistic and practical—you ought to have discussed and arrived at a mutually agreeable LWD between you, your manager, and HR. That would have even preempted this issue in the first place. If indeed there was a discussion and your manager and/or HR didn't agree with your request for 30th September as the LWD, then you ought to have followed the rules and served until 5th November. Further, please remember that it's you who needs the experience documents for your career records—and quite possibly to be submitted to your next employer too.
Resolving the Issue Amicably
I would suggest that you call your HR or your manager and resolve the issue amicably. In the present-day hiring scenario, most HR will treat resignations differently—I know of cases where resigned employees were cajoled with counter offers, etc. But at the same time, they wouldn't like to be taken for granted.
All the best.
Regards,
TS