They may have your name and test number incorrectly matched to your profile. Especially if you have a unique name. My name is Shea'la and omg the amount of times I've had to get things corrected is astounding. Give them a call
Happened to me too, I just went to my doctors office and got the letter in person
I would check with them. My Natera profile showed a test sample received within a day or two and also noted the date by when I could expect results