You can try to do this: first, hold a class meeting to analyze and summarize the situation in the class at this stage. Of course, don't mention whose responsibility it is and which class Committee is not doing its duty. Doing so can not only explain to the classmates, but also explain the problems in the class clearly, suggesting that the class Committee can't go on like this. The key is how to say it.
Secondly, have a private meeting with all the class committees, starting with discussing the status quo of the class. Don't mention at the beginning which class committee hasn't done a good job recently. Let's bring up the situation in the class first, and then discuss how to solve these problems together. This will motivate the class committee. .
Pay attention to the attitude of each class Committee at the class Committee meeting. If you have a bad attitude or have something to say, tell them privately.
Secondly, the tasks of the class are often shared equally by the class committee, which should not be idle. You can publicly announce every activity and the class committee in charge, so that the class committee will be supervised by the whole class and will not slow down.
In short, in college, everyone puts their own affairs and good relations above the interests of the class. Therefore, don't take a tough attitude towards the class committee. Just like the class committee, if you push them too hard, it will be easy to tear their faces and they will not be able to manage any more. If you are a recognized monitor, convince those class committees.