Does the Services menu have a Bandwidthd entry?
If so, then your system has had the actual Bandwidthd package installed at some point, but an upgrade (or something) has somehow lost it from the installed packages list. In that case, from System->Packages you can install Bandwidthd, then uninstall it again. That will get rid of the menu entry, and the program.
Otherwise, post the output of pkg_info command. (You can then probably use pkg_delete to get rid of bandwidthd, but there might be other bits that could also be removed, and there might be other things installed or customised on your system?)