You will need geotagged images from that location to prove that the item is not there. If you have those (and can show the spot on Google street view through history), you can use the “property owner” form linked above as “Wayspot Removals.” Most report getting a result within 1 or 2 days using that method if they have all the right evidence to prove the wayspot is not there.
Don’t worry about the language telling you that you must be the property owner. Niantic knows this is a poorly written form. They have given us permission to use it for removals.