Is there a built in answerphone in this model?

Contact Argos. Ask if they will replace or repair under warranty. They are cheaply made and not built for longevity.

https://www.google.com/search?q=Binatone+1315

..

are u using BT1571?

The model number of a cordless phone can usually
be found on a small sticker underneath the battery
in the handset (eg, CS6229, D1680, etc.).

Take this model number to www.manualslib.com
to download a free copy of the User's Manual.

Good luck!

What model answerphone?

What make and model answerphone?

What make and model?

The KX-T7730 isn't an answering machine. You need to refer to the documentation for whatever answering/voicemail system you have it connected to. Alternatively, repost your question specifying the make and model of the answering/voicemail system.

You directed this question at me, but unfortunately I'm unable to provide you with a "real" solution at this time. FixYa has informed me that by providing you with this "solution" your question will then be made visible to other experts; hopefully one of them will be able to provide you with a real solution.
It also might help if you could specify the make and model of your phone.
Thank you for using FixYa.

The MFC 885CW does NOT have a built-in answerphone. It will connect to an external machine if you like.

Here is a link to the owners manual and if you like, you can download it. The section dealing with answerphone starts on page 55

http://www.brother-usa.com/ModelDocuments/Consumer/Users%20Manual/UM_MFC_685cw_885CW_EN_1339.PDF

you need the MODEL number. Try going to uniden.com and go to customer service/manuals. You might find it there