How can I decline doing a presentation at work?

The divisional manager, whom I provide financial support, has requested a segment presentation on existing controls for procurement procedures. However, I am hesitant, as these procedures are well-known to him and fall under his purview. His request appears to be for me to address his deputies, over whom I have no authority. Past attempts to ensure procedural compliance have resulted in victimization and accusations of being petty and childish from him and his duty managers. Now, following a creditor clerk's complaint regarding procedural issues he is unwilling to address this directly, he has inexplicably tasked me with presenting this information at a last minute strategic meeting he organised. My previous attempts to raise these issues resulted in a meeting where I felt reprimanded not only by my direct managers, but also his manager. Given my financial support role, I am consistently questioned about departmental losses and budget overruns by his manager. This presentation request pertains to issues I have repeatedly addressed. I suspect the creditor clerk may be manipulating the situation to my detriment. Because he feels like i should be enforcing controls whereas the divisional manager should take control of.

Updates
4 mo
My suspicions about the creditor's clerk arose when the meeting i was reprimanded took place. Because instead of addressing the issues we face he didn't. Regarding the Presentation I told him that the divisional manager wants me to present and he went like maybe it will be a good thing. I explained my proactive approach in addressing each assistant manager individually and he went like a presentation would be good because you will be addressing everyone and not sidelining anyone.
Updates
4 mo
Felt like he was told something and as always I was painted in a bad light.
How can I decline doing a presentation at work?
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