What steps should passengers take to get assistance from United Airlines customer service when dealing with last-minute flight changes, cancellations, or lost baggage?

After my connecting flight was canceled, I contacted United Airlines customer service https://united-airlines.pissedconsumer.com/customer-service.html for assistance. The representative rebooked me on the next available flight and even issued a travel voucher for the inconvenience. Thanks to their prompt action, I reached my destination with minimal inconvenience.