Ok. I've entered the code, pressed "Ok", and heard the beep. I've tried the phone on all three of my chargers. But, still, the display shows "Flat Battery". Any ideas?

One of my handsets would no longer charge, so I just replaced all three of my Beocom 6000 handsets with new batteries. But, now that the battery charge has been depleted, they won't charge from my chargers. I called the B&O store and was told that once I replaced the battery, I should enter the code 9#9#9*655 then press 'ok'. Is this