Sounds like an LG...I've got one and really enjoy it, but the temps can be a challenge.
Remind yourself that small turns on the thermostat are the way to go...and they take a while to register as a change in temp. Make a small change and then leave it alone for 20 minutes or so, then make another adjustment.
My experience is that the humidity will increase as the temps decrease. If yours is an LG and your climate is similar to mine, the sponge and fully filled water trays should do the trick.