All the Dbs on my Yamaha P-35 are muted

[Emilyric]

I've got such a bizarre problem. My Yamaha P-35 has been playing just fine but today when I attempted to slow the metronome down for the first time, it wouldn't slow down and also resulted in all my Dbs not making a sound when I play downward from the F. They play just fine going upwards or playing scales or even going downwards from an Eb. It's so weird. I've tried resetting the keyboard and I've tried turning it off and banging it while holding it on its side, but nothing has altered the problem. Any ideas of what I need to do to fix this?