Just had a terrible experience with DL
My niece was travelling JFK-TLV with a disabled child. 6/1 flight was first delayed then cancelled (our mistake was using curbside check-in, had we checked in at the DL counter, we might have found out earlier and in time to be protected on another airline same night).
After spending hours at terminal, she was sent home and told she's confirmed on the 4pm flight the next day, but told to come to airport as early as 12pm, as there will be two flights leaving. Multiple requests to be protected onto ELAL were denied.
Luckily, I decided to call DL on her behalf in the morning, to see if she can get something else, and while speaking I found out that they just took her off the 4pm flight which she was confirmed on, and put her on a 6PM DL flight (which was the flight that replaced the cancelled flight from last night).
I told DL agent that this is unacceptable, but they said that if I want to be protected on LY, that flight actually leaves an hour later. Eventually they agreed to confirm her back on flight 466, but said that can't get two seats together, that she should talk to a supervisor or "red coat" at the airport and get that done.
She arrives at the airport around 2pm, asks right away for a red coat, who says he will most definitely get her two seats together, and hands her boarding passes.
When she arrives at the gate for the flight trying to board, she is told that she's booked on the 6pm flight, and can't board this flight. She calls me crying frantically, and I tell her to ask for a red coat right away. He comes and finally gives her two seats at the back of the aircraft, so seemingly all is OK.
When she finally gets to her assigned seat (carrying her disabled child in hand) she discovers that someone else got those seats assigned and is told that she has to go on the next flight. Luckily she called me then and there, and I instructed her by no means to go off the aircraft unless she's seated together with her child, even if it means they have to call police.
While I was on the other line trying to call DL, the issue got resolved by the other person being reseated elsewhere (I suggested a couple of times that she get bumped up to J but any time I mentioned that I was told that is not doable).
I don't know what will end up happening with the luggage, but I am guessing that it is on the other flight.
What compensation might she get. She flies several times a year TLV-JFK-TLV with her child.