matching regular expression help

hello,
   can someone help figure out what's wrong with these statements? I'm trying to compare correct format of phone numbers and it seems to not detecting the "-"

set phnum = ""
set test = 0
while ($test == 0)
        if("$phonenum" =~ [0-9][0-9][0-9][-][0-9][0-9][0-9][-][0-9][0-9][0-9][0-9]) then
                  break
          else
                 echo "Need to enter phone number in correct forma pleaset"
                   set phonenum = "$<"
         endif
end