Experienced a mechanical delay last months which results in a forced layover of 24 hours. Instead of filling in web form complaint, then wait, then get bot response, then reply back that 5000 points is unacceptable, then wait, then wait, then maybe get an email, then need to submit receipts, etc., I went old school and mailed a physical letter explaining the situation, what reasonable expenses I thought should be reimbursed, and a request for some additional compensation. Copies of receipts were included.

Mail was sent on August 5 to:
American Airlines Customer Relations
P.O. Box 619619
DFW Airport, TX 75261-9616

Thirty days later and I have not received any form of acknowledgement/reply.

Historically, I've had good luck with the following address: (which was previously listed as the customer service mail address)
American Airlines Customer Relations
4000 E. Sky Harbor Blvd.
Phoenix, AZ 85034

Does anyone know if the address I sent to is correct (DFW Airport)?