I was on the LHR-LAX flight that got canceled yesterday. We just arrived a few hours ago which was a delay of about 18 hours. UA was very explicit that this was an MX issue, and I have written communication from them confirming that. My understanding of the UK regulation is that this entitles me to £520 in compensation.

However, when I go to their united cares website it’s only offering me $300 in ETC. I don’t see any option to escalate this on the united cares website, nor can I find any official government channel on the matter. Is this simply a case of calling UA until they give me the money? I’m a bit puzzled why they aren’t offering the legally required amount since everything I’m reading online seems to be crystal clear that I should be getting the full £520.