Please try removing the rechargable batterys and charging them in a dedicated charger.
It sounds like your batterys are completely discharged and the base station is having issues with that.
Hi, I have the same problem. I've tried two new sets of rechargeable batteries but they will not take the charge although the charge light is on. When I put non-chargeable batteries in the phone works but can't get the pin number when I press the base unit call button. If you get a solution please let me know.