How do I know Rec has been received?

<p>Since my teacher sent Recs via mail, do I have to register the recommendation teachers on the application? The problem is my math teacher seems doesn't have an email.</p>

<p>And if I doesn't register the recs on Michigan's application before 2/1, will they think I passed the deadline???</p>

<p>Urgent~~please help me. Thank you</p>