While you wait for answers, we may have found some information which could help you.
Success
Message
TAM FULL on Binatone 1420 Single, base holds old messages th?
How do i clear the TAM?
BT 4600 phone problem?
Problem with handsets?
BT 4600 twin one handset bot ringing?
How can I repair my phone?
My bt freestyle phone don't ring or con?
BT Studio 4500 cordless telephone?
How can I mend my BT4600 (1+1) phone?
How can i get my handset to speak with the caller?
Bt 4600 phone?
Battery cover?