If you want to make upper management aware of your situation and/or file formal complaints with United and/or the United States Department of Transportation then this should help:

United’s New CEO Made A Website Just To Get Your Feedback:
The website:  https://unitedairtime.com/

On the website new United Airlines CEO Oscar Munoz says:

This site is our way to connect directly with United’s customers and employees to answer your questions and get your feedback about how we can become the world’s best airline.  Your feedback will be central to help us progress toward that goal.  It is designed to be an ongoing conversation, and we will strive not only to honestly answer your questions and concerns, but also to implement your input.
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If you want to file a formal complaint with United please make sure you do it through Customer Care and using this form:

https://www.united.com/web/en-US/content/Contact/customer/default.aspx

Please note that the minimum response time to hear back from the Customer Care team is 3-5 weeks (depending on status) so don't expect an immediate response.  Make sure if you do file a report with the CC team that you get a CASE ID NUMBER as the CC team should send an automated response confirming receipt of your report.  Within this receipt there is a Case ID number and without it United will tell you to please submit your request again.

If you submitted a complaint and “didn't” get the automated response with a Case ID number then check your SPAM folder to see if it was diverted there instead of your In-Box.

NOTE: due to the grief and hassle United put you through you may also want to ask for a "Goodwill Gesture" in your formal complaint.  The screenshot below from a frequent flyer that appeared on United's Facebook page explains why you ask for a goodwill gesture instead of compensation.

















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You should also make sure to file a complaint with the U.S. Department of Transportation's (DOT) Aviation Consumer Protection and Enforcement agency and this is why:

All complaints are entered in DOT's computerized aviation industry monitoring system, and are charged to the company in question in the monthly Air Travel Consumer Report.  This report is distributed to the industry and made available to the news media and the general public so that consumers and air travel companies can compare the complaint records of individual airlines and tour operators.  These complaints are reviewed to determine the extent to which carriers are in compliance with federal aviation consumer protection regulations.  This system also serves as a basis for rulemaking, legislation and research.  Where appropriate, letters and web form submissions will be forwarded to an official at the airline for further consideration.

Complaints are broken down into 3 categories: Safety and Security Complaints / Airline Service Complaints and Comments / Disability and Discrimination Complaints and you can reach all 3 at this link:

http://www.transportation.gov/airconsumer/file-consumer-complaint

You have 3 options when it comes to submitting a complaint: you can call, write or use their web form.

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For information, advice, tips and secrets from the world of aviation travel you may want to check out my "United Airlines Tips & Secrets" Facebook page:
https://www.facebook.com/United-Airlines-Tips-Secrets-157698367687655/