Free Log In Campaign Timer Broken?

[worldofneil]

I do not have an active subscription to the game. It expired in November, right as the Free Log In Campaign started.

There's your problem I'm afraid. From the campaign page (which you linked):

Registered service account must have been inactive for at least thirty days

Your account wasn't inactive for 30 days before the campaign started so you're not eligible. It started on November 13th, so you would have had to expire ~14th October, not November.

[NaiaLalita]

I'm sorry if I didn't make this clear.
I did get to log in. On the 19th, the 20th, and the 21st.

My account was inactive for the 30 days. The stipulation was that you needed to have a 30-day-inactive account prior to logging in at any point during the length of the campaign.

My subscription time expired on November 12th, 2018. My account qualified to participate in the Free Log In Campaign on December 12th, 2018.

I intentionally postponed logging in for the reasons I already stated (primarily, participating in the Starlight Celebration; secondarily, extending the demolition timer on my private housing by as long as possible)

I did get to log in, and I did so following the example given in the page - however, instead of getting a fourth day of play time that expired at 11:59 p.m. (local time)... I cannot log in at all on this fourth and final day.

TL;DR:
I planned to use this campaign from December 19th, 2018 to December 22nd, 2018.
I successfully logged in on the 19th, 20th, and 21st - but am unable to log in on the 22nd, which should have been my fourth and final day of play covered by this event, per the event's own stipulated text.