REMOVE CALL WAITING

I have called four times and NO ONE CAN HELP ME to get CALL WAITING, VOICEMAIL, AND CALL FORWARDING removed from my work phone number. When I called in again , I was told that it had been removed from my phone line. When I tested this for myself with two separate phone numbers calling into the line while I was on call, the call waiting notification still came through on the line.

I need to emphasize: I cannot work without ALL call features, especially Call Waiting and Voicemail, removed COMPLETELY from my phone line.