Originally Posted by
Kieron
That's your issue. Per
the partner page:
To qualify for mileage accrual, please note that your flights must fall within the eligible flight number range below [400-1999] and your flight must be marketed and operated by KLM.
Some people have had success submitting KLM boarding passes showing the KLM flight numbers after the fact, but it's not a guarantee.
Boarding passes are key. I've heard one or two people say that DL codeshares on KL metal were automatically credited, but that didn't happen for two flights I took in early September. I sent my boarding passes and a copy of my Delta receipt in this weekend, and they showed up in my account this morning. I did supply the ticket number of my traveling companion, but I didn't have her boarding passes, so she'll have to check if they credited her as well--Alaska didn't even send me any kind of acknowledgment email after crediting me.