I have the opposite situation. I flew KLM from YYZ-AMS on Sept 4 (DL ticket stock) and flight was delayed over 4 hrs on a brand new 787 (2 weeks old) due to a deffective hydraulic part. I submitted a claim for EC261 compensation to KLM on Sept 13 and got an auto reply and nothing else.
I communicated with KLM's Facebook team and they said I needed to submit my complaint to DL which I did on Sept 21 and did not even get an auto reply with a case number. I resubmitted to DL on Oct 2 thinking I had maybe done something wrong, but again no auto-reply/case number.
What is the correct procedure for submitting a claim to DL? I would like an acknowledgement that someone is working on this. I've hear NOTHING from either airline (other than KL's auto reply).
I used the Contact Us link > Voice a Complaint > Before Trip.