I second (or fourth) the suggestion to file a DOT complaint. They are in violation of DOT rules, they were required to provide accommodations to you.

Complaints can be filed here: http://www.dot.gov/airconsumer/file-consumer-complaint

File, and you will get results. And it also helps all of us as it raises UAL's dishonest conduct with DOT, which may eventually force them to change their "texas cheat-m" ways...