I am a homeschooler with a score that would almost definitely qualify me for national merit. The National Merit Corporation sent a letter to my principal (parent) in April saying that I made the commended cutoff. The letter said that if there was any issue with my information, then my principal should respond to them. There was no issue, so my parent did not send a response to them. We have yet to receive a letter in the mail confirming my semifinalist status. Should my parent have responded anyway? Is this going to eliminate me from the competition?
No, your parent did the right thing. There was no need to respond.
At this point, I would simply assume the letter got lost in the mail. Have your parent call the NMSC and ask. They are extremely helpful. Chances are they will make your parent wait till after Sept 15, but this will all get sorted out.
You will be fine, but I understand how frustrating it must be right now. In the meantime, make sure that you have everything ready to go - essay, awards, EC list, transcript, etc. You will also need to find a person who will endorse your application, preferably a teacher who worked with you.
I am a homeschooling parent, and S22 is my second kid going through the process. I am 100% sure no response was required. Your parent will have to fill out their section of the NMF application, but it’s less involved than the GC part of the common app.