This same thing happened to my"Ultimate" PO. I didn't use any case opener as I didn't have any, so I used some duct tape rolled around my fist. With the bracelet off, I put the bottom of my fist on the back case and twisted. Came off pretty easy.
As Usil mentioned, some PO had missing screws, I was one of the lucky ones that didn't have any screws on there.
I did use super glue as I didn't really have anything else around, but was very careful and seemed to work out. Did this three days ago, and everything seems to be holding up well.