Have you tried contacting Phone Power? Pretty sure if you send an email to them, they'll change it for you. The info is all listed here: What will show up on my Caller ID?
Or did you request them to change your caller ID and they flat out refused? As you said they did in your other post here? [General] Change CNAM, Caller ID Name
If so - that's a whole other issue, probably something you'd have to contact management about.
Hope you get it taken care of!