To speak to a LATAM Airlines agent, you can call their support team at +1.804.853.9001 After the call, you'll need to get past the IVR phone system to speak with a representative. 
You can also contact LATAM Airlines by sending a request through their help center. 
If you need special assistance, you should contact LATAM Airlines' call center at least 48 hours before your flight. For example, if you need extra space in the cabin, you can purchase an additional seat by calling the contact center. If you're traveling while pregnant, you can request special assistance by sending a medical certificate through the contact form.