how can i fix my BT freestyle 1025 answering machine?

BT Freestyle 1025, base unit has gone dead,no charging light showing and no dialing tone from hand set but the display on the base unit is showing the normal red 0 which shows no messages recorded.
Batteries in hand set are two years old and it tries to connect to the base unit briefly then turns itself of again.The base unit was emitting a strange bee boping sound from its speaker just before it went dead,do i need a circuit diagram to sort it,if so can you help?