File a complaint against a business with BBB, search for a business to file a complaint against, or find out the status of a complaint you submitted. File an Online Complaint.To file a consumer complaint online, please click below, fill out the form and click "Send. You are welcome to call 311 with any questions. When filing a complaint, please explain your problem simply and concisely. Postal Inspectors suggest that, before completing a business transaction, contact the Chamber of Commerce, Better Business. Use our consumer assistance directory and sample complaint letter to file a consumer complaint. Use our consumer assistance directory and sample complaint letter to file a consumer complaint. Materials, and forms you fill out. Look in the Table of Contents (p.