First off, I understand that the SE team is probably swamped right now. If they aren't, I do think that they really should be.
Still, I posted about my resignation as a community moderator on Oct 1 21:39 to 21:40 UTC. I e-mailed Stack Exchange a few minutes before posting that, wherein I requested to resign as a community moderator.
I also later updated the relevant site profiles to indicate that I am resigning as a community moderator.
I have also used the contact form earlier today (Oct 6) to draw staff attention to that e-mail. The contact form doesn't send an acknowledgement that can later be referenced, so I'm not sure of the exact time when I did this (I probably should have kept notes of that, but alas).
In the meantime, a SE employee posted An Update to our Community and an Apology on Oct 3 15:44 UTC.
It's now Oct 6 18:37 UTC. Sure, today's Sunday, but Oct 1 was Tuesday.
I have not yet received as much as an automated reply, never mind any reaction from an actual human being.
My previous experience has been that SE staff has been fairly prompt in responding to e-mails. I also see that other moderators have both resigned and been reinstated, so they are clearly handling some such requests.
How long should I expect to wait before I receive a response?
Update: My moderator access was revoked on Oct 8 around 11:35 UTC, in response to my original resignation request e-mail, to which I received a reply to that effect from SE.