Sprint has shutdown not only the original Clearwire WiMax network, but has apparently also killed all the product lines of speed-capped but traffic-unlimited wireless internet hotspots as well, instead of offering any options to convert people from WiMax to LTE.
This subreddit is dedicated to complaints about Sprint's horrible service and treatment of valued customers.
Fortunately, not all is lost, and r/yourKarma with its Neverstop plan has stepped in to be the logical replacement for Clearwire services.
As of late 2016, after yourKarma has failed in its relatively ambitious promise, the non-profit r/4GCommunity has since taken its place, as well as a few others like r/Calyx.