BT provide a feature called redial or 1471. This allows you to redial the number which called you last.
If you receive a call from someone and you were unable to answer, this feature is ideal for your business
as it allows you to simply dial 1471 into your handset and your phone will redial the previous number for you.
To get this feature activated against your account, contact us at email@example.com or 0333 202 5000 option 1 for Customer Services then option 2 for Landline and Broadband and a member of the team will be happy to assist.