DCMA (Defense Contract Management Agency) has an ombudsman to investigate contractor complaints against maladministration. This ombudsman is not exactly a specific person but an email address that serves the same purpose.
Source: PNWC’s Government Contracting Update: DCMA’s Ombudsman
New Regulation Formalizes Ombudsman Practice and Identity for IDIQ Contracts
An ‘ombudsman’ is an official charged with addressing and/or investigating the interests of individuals’ or companies’