I had automatically my KLM frequentflyer number in the reservation when added it to my account. At check-in at the airport I let delete my FB Platinum. But they weren't able to ad my Skymiles number. Was an outside station. And they didn't know anything. So my boarding pass didn't had any frequent flyer number. Also didn't get miles in FB.
When my skymiles number had been added in the past I had almost never problems with miles. Only with flights with Latam. My problem is that Delta don't respond when I want to credit the miles later. Sometimes I am not sure where to accumulate the miles and don't ad my frequent flyer number. With FB there is never a problem I call and everything is done. With Delta I am using the form on the.website,.writing complaints, calling but never get any response.

I was a long time a Delta diamond, but then got ill and could not fly for more than one.year and got down to silver. I emailed Delta four or five times if they can let me my diamond because of the issue of my illness. Never got an answer. That's the reason that I changed to FB, because I was upset that nobody answered me. But sometimes I want to collect the miles in Delta because some bookings gave a lot of more miles there and I have no time issue to defend my FB Platinum.

So at least it is a problem of communication and I have no idea how to solve this problem.