Carl Steiner walked to the window of a small gray building near downtown Phoenix and gave a worker his name. He stepped away with a box and a cellphone bill.

The box is what Steiner had come for: It contained black and red Reebok sneakers to use in his new warehouse job.

Steiner doesn’t have a permanent address. His letters and packages are delivered to a mail room for homeless people in the building at the Keys to Change campus, a collaborative of 15 nonprofit organizations that serve those like him.

He and thousands of others have received mail here for years. They use the address for job applications, for medication, to receive benefits like food stamp cards and even to vote. And for 20 years, the U.S. Postal Service provided at least 20% of the mail room’s budget.

But last month, the postal service ended its support of $24,000 a year because a nearby post office is “able to fully serve the community,” a spokesperson said in a statement to ProPublica.