The extension isn't automatic, you have to claim it yourselves. To do so go to this page: http://www.livejournal.com/pay/claim.bml.
The full post from

ETA: And this applies to any paid Communities too - thanks
Well here we are, the final day of 2020, I can't imagine there are many people who are sorry this year is over. I am ending my month of Christmas…
For the penultimate day of 2020, I am cheating a tad as I shard this picture last year. My defence is I love it so much, plus I have some new…
For the ante-penultimate day of 2020 I bring you something a little different. I came across this on the web and thought it was so clever, it…
Well here we are, the final day of 2020, I can't imagine there are many people who are sorry this year is over. I am ending my month of Christmas…
For the penultimate day of 2020, I am cheating a tad as I shard this picture last year. My defence is I love it so much, plus I have some new…
For the ante-penultimate day of 2020 I bring you something a little different. I came across this on the web and thought it was so clever, it…