File a DOT complaint to at least get someone competent at UA to review the situation. $1000 is plausible as a refund for the cancelled return, but may not be correct and it's weird to phrase it as compensation rather than a refund of the airfare.
https://airconsumer.dot.gov/escompla...nsumerForm.cfm
The $6800 you spent on self-help is on you/your travel insurance, nothing to do with UA.