Today it took 10 tries just to get through on their 800# (busy signal, your call could not be completed..., stutter tone, etc.) then a 2 hour wait to speak with an agent.
There is no callback option.
They do have a "special" number while on a trip--I didn't want to use that number
I dealt with this back in March. Listened to hold music for the entirety of a 7.5 mile run, plus an hour before and after. It’s bad, and Delta needs to figure something out.