only way to contact that user is to write a reply on your google-my-business panel
you can flag their comment from inside and elevate it to the google moderation team
what most people do..write a reply to put yourself in a good light and flood your listing with 5-star reviews so that 1-star...
I would love to be able to check out the new myspace and see if it is going to be worth investing time in in. I am wondering if anyone has a spare invite?