Checking in this evening/morning for my flight from DFW-SAL-MDE later today, and I find that my paid Business Class ticket booked last October through UA (online) on AV, confirmed with a paid receipt showing Business, showing online as Business, is booked in Economy on AV. A call to UA that lasted 64 minutes, went through 4 supervisors, the agent could see it should be in Business, but the supervisors all say no. They said that I would have to pay an additional $950 to upgrade at this late date. I need to go to sleep, but my hair is on fire. With so little time until my departure and a list of things I must do prior to departure (including sleep), I'm just going to be stuck flying in E, but I'm not done. I'm trying to decide whether I should write to UA first, or just go straight to the DOT.