"Original Routing Credit" is not a concept that applies with partner carriers. You can only request ORC when you are on a flight operated by the same carrier that operates the mileage program you are crediting to. Partners do not have the ability to deposit miles on anything other than what was flown--there simply isn't a mechanism for them to do so. The only people who can touch your mileage account is AS customer care, and they're not going to take responsibility for something that DL did. DL can only give you vouchers or SkyMiles, neither of which will help you in this case.
Also, ORC only generally applies for day-of-departure IRROPS. Schedule changes where you're notified in advance generally don't qualify for ORC.