https://discuss.tindie.com/t/full-list-of-official-delta-airlines-customer-service-contact-numbers-the-ultimate-official-guide/525417 https://discuss.tindie.com/t/complete-list-of-delta-airlines-customer-service-contact-numbers-in-the-usa-the-ultimate-official-guide/525454 https://discuss.tindie.com/t/99-full-list-united-airlines-toll-free-usa-contact-numbers-a-step-by-step-guide/525490 https://www.companyofmen.org/topic/163050-complete-list-of%E2%84%A2%EF%B8%8Fdelta-airlines-%C2%AE-customer%C2%AE-service%E2%84%A2%EF%B8%8Fguide/ https://www.companyofmen.org/topic/163053-full-list-of-official-united-airlines%E2%84%A2%EF%B8%8F-customer%C2%AE-service/