“No, sorry, I cannot help you with giving an interview.”
Or:
“For this year I had to decide to not give any more interviews.
So, sorry, I cannot help you.”
The result is the same. No interview.
However the first response is a ‘no’ to a person.
The second response is a ‘no’ to giving interviews.
The second answer is a lot easier to give
and a lot more pleasant to receive.