what did you record to? maybe its the medium that you recorded to that is set wrong? does it only comer across the left channel after you record? or all the time?
make sure that what you record to is set to record in mono or stereo, maybe the software was recording hard panned to the left, but an accident you made with the settings
i also have the same mixer, and i had problems with the power, also a pair of behringers monitor speakers i got were problematic when i first got them, maybe its a problem with the unit, because from my experience behringer stuff is prone to being faulty right outa the box