I'm glad you acted quickly and with resolve to the CPAP problem. I'm waiting for a new machine, so I wonder if they'll send me yours? (No, I'm going through a different DME supplier.)
I recall that you got good sleep during your sleep study. So it suggests that if you had a machine that was set up properly and working properly, maybe the therapy would work for you.
Those CPAP devices are pretty crude things, though. They're essentially a computer-controlled reversed vacuum cleaner.