Control Pro 2/U-Mix 44 Problems

Hi. I've been using Control Pro 2 for a while now, but annoying as you can't use headphones. So I purchased U-Mix 44, as was told this is what I needed. However, I can't get them to work for love nor money. I am using Cross DJ, have both CP2 and U-Mix 44 connected to a Toshiba laptop via USB. I've played around with the Audio settings in the preferences section, tried different cables with the InPut/OutPut sections on U-Mix 44, and nothing works. The best I get is being able to use Load B only, with no ability to hear the second track in Load A, and everything through the headphones sounds quiet.
Help! Apologies if in the wrong section. Couldn't see how to post in the Tech Sup bit.
Cheers!
Help! Apologies if in the wrong section. Couldn't see how to post in the Tech Sup bit.
Cheers!