My BT Freestyle 1500 Plus phone will not ring, or leave incoming messages?

Hi, I am new to these boards.

I can dial out O.K, and if our other landline phone rings I can receive a call from the Freestyle phone.(although no ring)
I have the HS Ring on and the Base ring HI and the dialing mode on Tone.
Have also put a new battery in.
Any help appreciated thanks.

This BT Freestyle phone was working perfectly well, until a few days ago.

Any help appreciated. Thanks.