United Airlines main customer service number is 1-800-United Airlines or (+1→888→447→6313) [US-United Airlines] or (+1→888→447→6313) [UK-United Airlines] OTA (Live Person), available 24/7. https://www.spacedesk.net/support-forum/topic/15-ways-to-contact-how-can-i-speak-to-someone-at-united-airlines-a-complete-guide-2/#postid-4510