Recommendation letter not received

Anyone that is familiar with Stanford admission process can help me out? One of the teacher who wrote my rec letter transferred to another school this year, so he’s not in our school Naviance’s system. He mailed his rec letter directly to Stanford on Oct 27th, 4-5 days before my ED deadline. However, on my Stanford application status, his teacher evaluation is still missing. I did provide him with the mailing label and offline CA evaluation form, which should have my Common App ID on it.
I don’t know if it’s because the school hasn’t matched the application files with the mailed materials yet, or because there’s some problems with the mailing process. I’m freaking out right now. What if my mail got lost? I emailed Stanford to ask but they only gave me an automatic response, which didn’t help me much. Anyone has mailed their materials to Stanford before?

Call them. Anything else will be just a guess. If they don’t have it, you can ask you teacher to fax it to them.