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/five-ways-to-call-united-airlines-customer-care-full-guide-usa/#postid-4386