Do we need to use auto billing in order to keep the 3GB + 3GB alive forever?

Hey guys, I just found out recently that going in to this plan resets my stupid voicemail and probably other shit service that tries to rip customers off from Celcom. I can't seem to deactivate the voicemail with ##002#. Anyone knows how to? Also if any of u know what other value added service automagically activated for us please list them down here. Thank u very much.