Back in September, my sister-in-law flew to Europe on CO. She entered her WorldPerks number in the record (it appears on all of her boarding passes) but didn't get ff miles for the trip. She recently requested the credit but was told the partnership ended so she can't get the miles. Since there was a partnership when she flew, and since her WorldPerks number is on the BPs, we think she should get retroactive credit. She can't find a person to talk to who will listen. Delta told her "CO is no longer a partner." Does anyone know if there's a way to get the DL credit at this time?

Thanks in advance....