In the Uk we have the Trading Standards Dept which regulates Consumer trading Laws . with quite wide raging duties. www.tradingstandards.gov.uk

What office regulates trading standards laws on a local level in Canada and the US?

USA:

National: Federal Trade Commission
My State: NC Department of Justice (Attorney General's office)
Private: The Better Business Bureau provides a clearinghouse for complaints about businesses

Canada also has Better Business Bureaus ('bureaux'?).

Office of Consumer Affairs

Oh, and locally - The Business Practices and Consumer Protection Authority