“Most days, 25-year-old Chavonne can push her student loan debt to the back of her mind. Between short-term office jobs in the Washington, D.C., area, she drives for Uber. But once in awhile, a debt collector will get hold of her cellphone number — the one she keeps changing to avoid them — and it all comes back fresh. “I’ll be like, ‘Oh no!’ ” she says. “It’s a sad reminder that I owe somebody money!””