To deal with spam networks you need to create a spreadsheet with details of all of the locations, domain ownership info, url for Maps listing, how you know they are in fact spam locations. The more locations the better. Single listings do not move the needle. You need to show more impact than that. They don’t care about singles.
It has to include things that make it totally obvious to a Googler reading it.
Put the spreadsheet together, post the summary on the GMB forum. If you want to remain anonymous don’t use your primary email and send me the link to