I believe the link help chat told you to use is the link that is available at the top here:
I hate that it is called the “property owner” form, but it does get results. You get an automated email asking for proof you are the property owner even if you filled out that you are not, but just ignore that automated reply and wait for the next response.
If the misplacement is far enough that it appears to be abuse, you may want to use the abuse form at the top instead of the removal form.
That said, I am interested in whether Niantic will address this for you here. They have not addressed my rejected report I posted: Rejected duplicate report: Native American Mural One