ombudsman

om·buds·man /ˈɒmbʊdzmən $ ˈɑːm-/ noun (plural ombudsmen /-mən/) [countableC]

PGCsomeone who deals with complaints made by ordinary people against the government, banks, insurance companies etc 民情调查员，巡视官，申诉专员〔专门处理民众对政府、银行、保险公司等投诉的人〕

Examples from the Corpus

ombudsman• Insurance, building societies, unit trusts, banks have each developed an ombudsman scheme.• For example, the proposal for an ombudsman is sensible.• Sometimes exgratia payments are made as a result of a recommendation of an ombudsman.• Only when they have reached stalemate with the bank will the ombudsman then consider a claim.• He points out that customers must first complain to the Tessa provider before lodging a claim with the ombudsman.• The ombudsman has no power to order compensation for example.• The ombudsman will have power to recommend that a lawyer or professional body pay compensation, but not to compel payment.

From Longman Business Dictionary

ombudsmanom·buds·man /ˈɒmbʊdzmənˈɑːm-/ noun (plural ombudsmen /-mən/) [countableC]

someone who deals with complaints made by the public against government departments, banks, insurance companies etc. In Britain, the main government ombudsman is called the Parliamentary Commissioner for Administration

You can apply to the Banking Ombudsman for arbitration.

Customers have the right to ask the Insurance Ombudsman to review their complaint.

Origin ombudsman