To contact Delta customer service, you have several options. You can reach them by phone 24/7 by visiting the Delta Air Lines website, selecting the "Help & Support" tab, and finding the appropriate phone number for your query. Alternatively, you can use the live chat feature on their website or send them an email by filling out the contact form. Delta also has a presence on social media platforms, where you can send direct messages or post comments for assistance. Lastly, if you have the Delta mobile app, you can access customer service features and support within the app.