Problem with xdj 700

 Hi, i've bought 2 xdjs almost 2 months ago in a store.

Until now it was all perfect but now one of my xdj seems to be broken.

When I put one track (from differents usb too) the track accellerate 200% times up, I can't put the cue point and when I move the jog wheel it happens the same when I put the track, so it's impossible to make beatmatching.

I tried to update the software but the problem didn't go away.

p.s. The other xdj function correctly.

What can I do?

Thank a lot!