The answer depends on whether the problem involves a visa, a petition requesting permission to enter the United States, or labor certification.
If the problem involves a visa, it probably involves the Department of State, which is the only federal agency than can issue a visa. There are two types of visas:
1. Non-immigrant Visa: A multicolored stamp placed in the passport, allowing the bearer to enter the United States temporarily for a specific purpose, identifies this visa.
2. Immigrant Visa: Not stamped in a passport, but is a packet of documents surrendered to an immigration officer at the port of entry.
The packet includes an approved petition filed by an individual, a business or an organization (such as a religious group) seeking to sponsor an immigrant’s entry into this country.
If the problem involves a petition requesting permission to enter the United States as an immigrant, or under certain circumstances, as a non-immigrant, such as for employment or as a fiance, the situation involves USCIS. If the problem involves labor certification, it involves the Department of Labor.