I would call the internet help desk (407-939-7765), who can help you with all IT issues. They can also book FPs for you, if you give them your reservation number and dates!
As for same day FPs in the parks, I know people love using their phones to do that, but the in-park kiosks work well, too. I always use those, having had zero success with the app. And yes, you can refresh on the kiosks; just click on "start over" in the right hand corner of the screen.