In the Silva v. Bell case, the federal government agreed with plaintiffs that “relief, in the form of a program to recapture and reissue the wrongfully issued visa numbers, is appropriate.” Visas were wrongfully issued in another category and court asked the agency to correct the mistake.
http://openjurist.org/605/f2d/978
In Silva, the court ordered the legacy Immigration and Naturalization Service (INS) to recapture immigrant visa numbers that were misallocated; the agency had erred by counting the set-aside immigrant visa numbers of Cuban refugees against the visa quota for all nationals of the Western Hemisphere between 1968 and 1976. Additionally, in Galvez, the court found that the aggrieved plaintiffs had been denied LPR status for which they were eligible and ordered the U.S. Secretary of State to issue visa numbers that would be charged against the remaining visa number allotment from the prior year. According to the Galvez court, the “
INS has a statutory obligation to issue visas to qualified applicants to the full extent of the annual quota limits established by Congress.”
8 U.S.C. 1156 - Unused immigrant visas
"If an immigrant having an immigrant visa is denied admission to the United States and removed, or does not apply for admission before the expiration of the validity of his visa, or if an alien having an immigrant visa issued to him as a preference immigrant is found not to be a preference immigrant, an immigrant visa or a preference immigrant visa, as the case may be, may be issued in lieu thereof to another qualified alien."
Congress did not specify what would happen if a visa is wasted by the agency's inefficiency, probably because Congress did not expect any visas to go wasted, specially when there is enough demand. Therefore, agency inefficiency and apathy should not be allowed to defeat legislative intent. Unfortunately, that is exactly what happens.