Failure to communicate 101

As I prepare to meet my Comedy class today, I keep finding myself rehearsing lines that would be more appropriate in Kindergarten: I'm doing this for your own good. This is hurting me more than it's hurting you. If I've told you once, I've told you 1000 times...

The thing is, I have told them 1000 times, or at least 20 times, and I've told them in various forms (orally, in person, on the assignment sheet, via e-mail) and they're still not getting it.

Well, some of them. At least half of the class needs a kick in the pants while the rest are doing just fine on this particular assignment, which offers students a significant grade-boost for a minimal amount of work. All they have to do is read the directions and follow them: submit at least 250 words commenting on a literary work before we discuss that work in class; they can earn only 5 points per submission, but over the course of the semester those 5 points add up to a full 100, which can make a significant difference in the final grade, for good or ill.

I use this system in general education literature classes every semester and I generally have to spend some time at the beginning reminding students of the requirements: Nice work, but your comment falls far below the 250-word requirement, so no credit this time. Or: Excellent analysis, but as the assignment sheet points out, you must submit comments before we discuss the work in class or you get no credit.

Usually all the kinks get worked out within the first two weeks, but here we are a week before the midterm exam and I still have students who have not submitted any comments (of the 10 due before next week) or who continued to submit comments that are too short or too late to get any credit.

And here's the thing: they're apparently not even reading my responses to their comments, because they keep making those same mistakes and they seem oblivious to the fact that they're not getting any credit.

I honestly don't know what to do with these students. I don't want to berate the entire class when only a few students are having trouble, but sending them more e-mails explaining the problem is unlikely to work when they haven't paid any attention to the messages I've already sent. How do I get through to students who have ignored everything I've ever said about the assignment, either in person or in writing?

I suppose I could tell them for the thousand-and-first time...