The provisioning of the device is done on the RIM infrastructure
RIM manufactures the BB's, the data side is up to the carrier. This is a carrier provisioning issue. It either has not data services or it only has BIS.
A BB will always work with a BES when it's connected via USB, data service or not. Wireless data transmission is not required when using USB.
Bell needs to correct your data plan. You should try to get transferred to RIM. They will prove beyond a doubt that it's the carrier. I PM'ed you earlier about this, I can save you the trouble of getting transferred to RIM. It's up to you.
Either way, the carrier needs to fix this, not RIM.