How to prevent the behavior of unsolicited users on the image check box?

Below you can see a section of a reservation system.

Photo of staff, name and call button

In this section, users should be able to select a staff member to book and also call when they need it. However, we received information that some users clicked the "call" button to select the staff instead of selecting the staff by clicking on the photo.

Here is a checkbox for the selected image.

The question is what should be done to avoid this misconception of the user.