Reply to Numark mixdeck channel problem

Hi everyone, first time posting so hope I am doing I right. I am only just starting out dj'ing and recently bought a numark mixdecj universal system (the one with ipod dock in the middle) it was advertised as ex-display stock, after receiving it I hooked it up with virtual dj and all seems to be working fine except for that when two tracks are playing both can be heard through speakers while fader is on channel 1 (all low mid high dials ect work on this side) but when I move the cross fader over to channel 2 nothing.. display works but no sound from either deck. I don't know if this is somting really simple to fix or if it is faulty. product from America and im in aus so hard to contact supplier. Any help appreciated.

Cheers A