Please try temporarily moving this handset to the test socket behind the Master Socket's removable faceplate, with a new or known good microfilter. If it is still no good there, does the phone take batteries & have they been changed? Do you have another handset that you could try in place of it?
The TalkTalk Community has now moved to a peer-to-peer support model. This means that the TalkTalk team will no longer be here to support with queries. Don’t worry, there are plenty of ways to reach out if you need to speak to TalkTalk directly. For more details check out the link here
How to contact TalkTalk Broadband - TalkTalk Help & Support
