Hrm, I knew Durlag's tower would be hard but...JEEZ!

Missile attacks dont' work, chromatic orb don't work...only thing that DOES work is Call Lightning but it did 20+ damage 2 times in a row and they still didn't die! What do I do....

Well...
What level are you?
I'd suggest fighting one by one by the patented "Cloudkill-fire at the fog"-technique.

Yah they are tough!

I believe Magic Missel works well. As well you are probaly going to have to slug it out with them so try luring them out a bit so you don't have to fight two at a time. Use spells like magic missels and lightning, when one of your fighters are severly injured move him back heal him with a cleric and potions, send him in again and take another injured fighter back. Hopefully they will be severly injured with spells so you will not have to do this to much. If you are in the open you can have one guy run around being chased while your mage fires magic missels.

One good thing about them is they don't respawn so once thay are defeated they are gone for good.

Ummm.. . . they're tough? Leave the Tower till later, go and level up some more. If you're already at the exp. cap and are having trouble I suggest you rethink strategy and/or party make-up.

All u need is as many web memorised as poss and a magical 2 handed sword. If you lure 1 out at a time and cast web u can attack him with the magical 2-h sword as ur out of his reach.

Wand of fire (A's scorcher), wand of Frost, Wand of the Heavens all work well.

Yeah, I used call lighting and that 3rd level skull bomb spell (and no it's NOT necromancy, more like destruction) and killed him in like 2 hits.

I set my tank upon him with a healer upon the tank then I arrow, slingstone and magic missile the piss out of him until he dies...works pretty well for me.