Those monsters scale to your stats... so no matter how high you go, it won't help

There are a few things you can do to tilt things in your favour though:
First, forget about boosting stats, particularly Moxie... ideally, your Moxie should be the same level as your Muscle or lower - This will effectively lower the monsters' level as the stats they scale to are lower. Second, equip the highest-power armour you have, regardless of other bonuses, as this will migitate a fair amount of damage. Third, use any buffs or equipment that directly boosts damage without also improving stats, as this will let you kill them faster without them gaining levels. And fourth, use a deleveling familiar like a Barrnacle.
[Edit] Also, just sent some buffs your way that should hopefully help some.