After 20+ years with Delta, I experienced something new earlier this month and would love any perspective folks can add.

In short, I was bumped from First Class to Main Cabin, despite having purchased my ticket with cash. The bump occurred literally while I was boarding at the gate - my Delta app still showed me in 2C, but after scanning the barcode, the machine spit out a slip with a new seat assignment - showing me in 33C.

The gate agent was confused, and eventually said there was a "glitch" that led to my seat being sold to another passenger. She said there was no way to reassign me to any other First Class seat.

The next day, after calling & writing to Delta to complain, a Customer Care person told me the downgrade was performed by a station manager at my departing airport (BWI), and that a downgrade can occur for many reasons, but she was unable to research and tell me why mine occurred. I was offered a refund of the fare difference, plus a $200 voucher. (I complained, and she upped the voucher to $300.)

It's worth noting that I'm a long time Delta Diamond, Million Miler, and Amex Platinum cardholder. Again, I paid for the First Class ticket with cash, not an upgrade. If I was "bumped," it seems hard to believe Delta followed any sort of typical prioritization in selecting me for bumping.

Can anyone offer insight into why a paid First Class passenger would be bumped at boarding time? (FWIW, the First Class cabin appeared full when I eventually boarded, so it wasn't due to broken seat equipment.)

I'm not even going into the atrocious way Delta handled this incident at every step of the way (no help at the gate; broken promises to get back to me; literally never a single apology for what happened; repeated statements from Delta that contradicted other statements, and turned out to be wrong; no offer of even a refund of fare difference until I had a 1+ hour conversation with an agent to complain; refusal of a manager to escalate further). My illusion of Delta as a world-class customer care organization has been thoroughly shattered, after experiencing how they handled my situation.

One lesson learned: you are (apparently) never, ever "guaranteed" a particular seat, even if you pay cash.