Carriers can certainly choose whether or not to offer wifi to their customers. If that was the case here, I would think your carrier would have been more up front about it when you contacted them. Trusting in the good intentions of others, I would guess that they just haven't figured out how to fix your issue as yet.
No hack that I am aware of to restore it for you, unfortunately.
1st Step in Troubleshooting: Do you have a BlackBerry Data Plan?
2nd Step in Troubleshooting: Pull the Battery.