I have been promoted to new role SDM , I am getting my ITIL service operation soon

My Question is in relation to my internal team.
My desk side support (one person) as ways says he is busy, so I tried to ask him what is his pressure points and he gives very lame reasons.
When I checked number of tickets that are closed he is very low compared to other team members. All you experienced SDM's please suggest how you deal if some says I am busy ?
Thanks you all...