Not to stick my nose in here but there seems to be the misconception that series 10 phones can be used on a BIS account. As JSanders had pointed out, that is not true. If you are indeed running a Z10 with a BIS account it likely will not work properly.
Honestly, based on the message that at least one of you is getting, the first place you should look for a resolution is to your original seller. Or course, BBerry can unblock the phone, but they are only going to do this if they are certain the phone has not been reported lost or stolen. If it has been they are not going to unblock it.