Ok, in short order -

Bought an upgrade to J upon checking in online. Paid by cc.

Flight then missed, due to weather delay on a connection (all AA, all one PNR.)

Customer service desk initially re-routed me through London, followed by a domestic connection on BA in Y. They specifically said the TATL part was in J (I asked twice to confirm this) but said because the London flight was imminent I had to go to the gate to get my BP.

I went to the gate. The GA there said I was in Y, commented i could never have been in J as it was full.

Back to customer service desk. Same agent. Denied having told me I was re-booked in J.

I asked to fly my scheduled flight, but the following day.

Agent says ok, but you're in Y.

I asked what happened to the purchased upgrade. Agent claimed I had to buy another one, or that would be 'stealing' and the airline 'out of pocket.'