From desktop website:

  1. Log in to your account
  2. Head to the 'Current Deliveries' section
  3. Click on the ID of the delivery you are interested in
  4. The driver's mobile phone is displayed next to 'Courier Mobile Phone'

From the User app:

  1. Go to your current deliveries
  2. You will be able to either text or call your driver directly from the bottom of the screen