How does this sound?
To Whom It May Concern:
I was recently made aware of the fact that the last interview day for the University of Miami Miller School of Medicine was on March 10th, and I have still not received a rejection email. Out of the 24 schools I applied to this cycle, this was the only one that I never heard back from. Even though I got offers from other schools, not everyone was as fortunate as me, and I'm sure that they would have appreciated hearing back about their admissions decision as soon as it was known.
I am writing this email to bring attention to how disappointing I found this conduct to be, and I hope that efforts will be made to avoid making the process more stressful than it already is for applicants in the future.