So a few hours after I resigned (only required to give 2 weeks notice, and it's to take a better paying job), my manager called me in to chat 1 on 1 and they asked me: please re-consider your decision to resign; sleep on it and tomorrow let me know if you still want to leave.
This request was a bit baffling to me as I had already vacillated on whether I should resign, but ultimately decided this other job was much better and then decided to hand in my resignation. I told them I would sleep on it, as they seemed sincerely sad knowing I was wanting to leave and felt guilty at that point in time telling them a firm, unambiguous no.
So I sleep on it, and the next day I have another 1-1 chat and told my manager I still want to leave. At this point, they assumed a very argumentative tone. First they tried convincing me to stay by telling me of all the supposed benefits of staying (guaranteed increase of salary in line with inflation, other organisation specific benefits etc.) and each time they enumerate each supposed benefit I respond with either a simple 'no' or a rebuttal that my other job is better paying and a better fit for me in other ways.
The discussion escalates further, as they start to ask me about my long term ambitions, and despite sensing hostility in their tone, I indulge their questions and mention I have a long-term interest in someday working in another completely different field. At this point they start berating me, telling me I would have to go back to school, nobody would hire me unless I get a whole new qualification, then immediately question my ability to even complete any future study by referring to supposed 'performance problems' I've had in the past.
Those 'performance problems' were completely made up by the way - never mentioned at all to me before that point, like in performance reviews or other 1-1 meetings. At this point I've realised I let this conversation proceed for too long, and very abruptly tell them I'm leaving and nothing you say can say will convince me otherwise. I then walked away hurriedly.
A couple days have past and now I hear that my manager is gossiping about me and trying really hard to paint the picture that I'm the one who blew up the discussion and that I've constantly misbehaved as an employee (which is utterly false). Apparently they've gone so far as to cancel my exit interview with HR, telling them none is necessary and that one was already conducted in a 1-1 meeting shortly my resigning (which doesn't make much sense because I would think that does not qualify as a proper exit interview, but apparently that is enough to convince HR to cancel it).
Should I somehow respond to this? Should I lodge a complaint to HR myself? Or should I just quietly wait it out and leave. My manager has started acting like the discussion never happened when they interact with me personally which is even more baffling.