well like you say by yourself it's be cause your combhat lvl is lower than the monster, let me explain:
i use isuptext to be sure that it's a monster, not a silly hat or a banana for example

but... if your combat lvl is lower than the monster's one there isn't isuptext('attack') that's your problem.
It wont attack because i made it only attack the mosnter when the isuptext is attack...
that's also the safest way, because when i don't check that, it just would right click every ting that includes that color, what can make you ban... and... yeah... that's not cool

Just try fighting a monster that has got a lower comat lvl than your character.
TIP: you know that spot near fally-port sarim? that cave... near that smither for that f2p quest (were you mine those bluerite ores for that same f2p quest btw) there are pirates (lvl 12 or 15 or something i thought) and hobgoblins(30-40 or something) maybe you can auto over there
