Ive just thought of something else.
Instead of being defensive and thinking of replies to fend them off, you could do on the attack. Here are a couple of questions:
"Is this a genuine offer where I have the genuine choice to say yes or no?"
"Are you going to force me to accept?"
"Would Jesus have forced anyone to be one of his apostles?"
And a few more phrases to add to the broken record:
"I feel that being forced to accept this offer would damage my spirituality" (again dont explain if pressed, its just what you FEEL, so no need to justify it with details)
"I dont think that forcing someone who does not feel ready is in the true spirit of Christ".
"My relationship with Jehovah does not depend on me accepting this position, and will not be affected by my not accepting this position"