I sent my PSAT score report in an email to the Exeter admissions office in December and received a reply from them stating that they received them. Everything else for my application was turned in on time, but yesterday I was sent a status update saying that my test scores were incomplete. Can anybody help?
You should call Exeter admissions. We had a similar situation with my daughter, where Gateway showed her transcripts being downloaded by Exeter, but received an email this week saying her transcripts were missing. I called the admissions office, and they were able to retrieve them from Gateway while I was on the phone. And they thanked me for calling. 
Yes, just call.
We had this problem with another school and another application platform. SSAT scores showed delivered on the SSAT site but the school had to “go look for them” and then manually upload them into the computer. Her application said it was incomplete for a while.
Schools are used to this happening, seems there are often tech glitches. It will not count against you so don’t worry, but do call or email.