Hmm, I'm sure I've read posts from others who are arriving in December and taking DME back to MCO in January. Who was the email from? If it was from DVC, I'd call DME directly at 866-599-0951 to inquire. The Disney Parks Blog announcement specifically stated (bolding added):
In light of this shift, when Disney Resort hotel bookings open for stays in 2022, we will no longer offer Disney’s Magical Express service for airport transportation, starting with arrivals Jan. 1, 2022. We will continue to operate the service for new and existing reservations made at Disney Resort hotels for arrivals throughout 2021.
I hope the information you received was mistaken!