All of the IJ holiday sales have ended and prices are back to normal. We will be putting Permanently Insane accounts on sale for their regular price before Christmas.
Have you tried switching to another e-mail provider, just to see if the notifications come in better? Squeaky has said that some of the e-mail providers are blocking InsaneJournal. A lot of people had this problem with gmail a few weeks ago, but it's since improved.
I would recommend switching an account to gmail, just as an experiment to see if your notifications come in. It would determine whether the provider is the problem.
Why would it do that all of a sudden? Certain journals work 100% while others don't work at all. And then on top of it I'll get about 50% of them sent to me retroactively. There's no rhyme or reason to it.