Was your phone bought new, or was it previously used?
If it was previously used (or even a return that wasn't properly wiped/refurbished) it may have a restriction placed on it from the previous company it was linked to.
If it was bought new - I can't help (don't know enough about this stuff lol) but am sure someone here will help, or even call tech support at your carrier.
If your device was 'used' and there is a remaining IT policy on it (restriction from the previous company that used it) you can look at this link, and it should explain things. Remove IT Policy - BlackBerryFAQ
by the way, think your work is fantastic!