I made the blackberry support person talk to RIM so that he may understand what's RIM saying about provisioning.
After the call my support guy tried something interesting to show that he is doing every thing right.
that is, if he take another handset and do an enterprise activation on that for my account it's working perfectly fine. It can send receive mails (wirelessly), surf web and do all the blackberry related stuff.
however, as soon as my handset is grabbed for activation / provisioning, the same problem occurs
like I said, if I attach it with USB cable, then every thing works fine with my device, but unpluging causes the problem to come again.