Slow metalic playback when screen goes off

I had a previous sansa before this, the fat white one that runs on AAA battery and it was wonderful before I lost it.

Because it was so great, i got the 1gb sansa express to replace it.

Now i seem to have a HUGE problem.

It wont play music properly.

The thing starts off well, but once the display goes dark, the music playback becomes slow and metallic, like a cassette player running out of battery.  If you do anything to it, press any button, then the song speeds up again the moment the screen comes on.

Does anyone else seems to have a similar problem or should I send this back to get fixed?

Have you called CS? It might be a hardware defect.