I have this in my style sheet, and the files are uploaded. Yet iPad doesn't use them and reverts to my secondary font, arial all the time.
Can iPad not show Segoe?
I was trying to find a copy of Helvetica Light, that Apple uses, but cannot trace it.
I am not sure, but could be that you are using only eot fonts. I am not sure If iPad supports eot. Perhaps you can do a test on Chrome, and see If it works. If it works on Chrome, It is definitely a compatibility problem in Safari.
You should add more font types to ensure compatibility between cross platforms and browsers. Add otf, ttf and svg format as well. As far as I am concerned ttf works on iOS and Safari.