The visa expired, and I20 was not renewed when re-enrolled, because it failed. I have been in the United States, and now I am refused a visa when I return to China. I need countermeasures urgently!

I think the visa officer will know that you are stranded in the United States when he asks your school to issue a new I20 and explanation, and it should be recorded in the system. So ask your school to prove that you didn't stay in the United States intentionally, but the school didn't tell you that you should leave the United States at that time. Actually, this is an opportunity for you. And your school doesn't want to take responsibility, so it puts forward the question of what can enter and leave the United States in the case of I20 failure in the explanation, and puts the responsibility on the immigration bureau. This is certainly not good for your visa. You still have to explain to the visa officer and see if you can get the school to prove that you have no intention of staying in the United States. It might be useful.