i think no need to use goto command

Code:
on $*:text:/^!(set|del)user/iS:#: {
  if !%x {
    inc -u10 %x
    var %s $replace($regml(1),set,1,del,0)
    if %s && $istok(%nick,$2,32) || !%s && !$istok(%nick,$2,32) {
      notice $nick $2 $iif(%s,already,doesn't) exists!
      halt
    }
    set %nick $iif(%s,$addtok(%nick,$$2,32),$remtok(%nick,$$2,1,32))
    notice $nick $2 has been $iif(%s,added,deleted) $+ !
  }
}

P.S: not tested


WorldDMT