From The Boston Globe: when Boujemaa Razgui flew from Morocco to Boston, via JFK, his thirteen handmade flute-like instruments were destroyed by U.S. Department of Agriculture employees. Razgui arrived, found out that his flutes did not, was given a phone number to call, and was informed that his instruments had been destroyed because they were mistaken for reeds.
The entire logic behind having an administrative agency is that the agency can develop in-depth, specialised knowledge of a field that Congressmen cannot. The agency can then take that knowledge and apply it to a modern, complex society. However, the Constitution does not provide for an entire alphabet soup of administrative agencies (it does provide for a post office, patent office, and copyright office, among others), let alone proper oversight of them.
I doubt that a single Congressional reelection campaign would even mention the destruction of Razgui’s flutes, let alone whether or not Congress is exercising enough authority over the Department of Agriculture or whether rogue employees are acting inappropriately with little oversight. That leaves Razgui, and anyone else caught in his situation, with no remedies at law or the ballot box to fix this situation or prevent it from happening again.
Of course, this is but one illustration of the ways in which an unelected, unaccountable fourth branch of government is able to act with impunity. (As I frequently point out, as bad as the worst customer service is, you can either sue a company or take your business to a competitor. The US government denies us both of those options.)