I’m diamond with delta for a couple of years and they audited me for having made some bookings with only one of my first names claiming there were different people using the account. I tried talking to them in every way possible including diamond line and being transferred to supervisors et etc and emailing customer service and twitter and nothing helped, they were saying that it is a special department handling these stuff and there’s no way to contact them.
I needed to make a reservation using miles so I emailed HQ and someone got back to me within 48 hours, apologized and fixed the issue right away.