I don’t own a forum [anymore] but I think that the user probably wants to leave and doesn’t want to leave at the same time. So I’ve never experienced this or was the person doing this, but I know some people who want their account to be suspended multiple times but end up staying. It’s usually because they want to leave sometimes and change their mind and the process repeats.
I think you should ask the user if they truly want to leave and see what they say. If they say no, then maybe ask the user to only message you guys when they truly do not want to be in the community. If the user says yes, then maybe bring up how they’ve asked many times and stayed active.