Understand that sponsors are just that. Sponsors. They don't have any formal mental health training. They have went through the steps. That's it. I actually backed away from sponsoring anyone at CR (and I did have some training) for this reason. Just because what was right for me, and my situation, did not mean that it was right for everyone else. It clearly states in the steps that to make amends unless to do so would harm someone else. It's harming you, giving you anxiety. So he should not be doing so, he should simply leave you alone.
Believe me, your not responding is his problem, not yours. You continue to do what is right for you. Don't be manipulated by him, or his sponsor, into responding when you don't want or need to. It's not your job.
Hugs to you.