Once again, if you are an adult working in a professional industry, you must see that what you are doing here is like a guy crashed in your house with the car and you drove away and went to the driving school to complain about him. There is a police, first, lawyers, and then talking to a bunch of random people on the forum that have no power whatsoever to do anything about this.
So your first act should be to contact the company FIVERR using their contact form. Wait for their reply. And then if you are not happy with their reply to come here and vent about the one user of Fiverr who is behaving unethically.
I have a business web page and blog with the possibility of comments. Every month one Pe___ enlargement guy and medicine for foot guy somehow find me and leave their comment. I erase them and move on. The moment I put my web page online I am exposing my self to life forms with intelligence and lifeform without intelligence but still, somehow they know how to place a comment and write emails.
You live on Earth. With humans. Humans are complicated.
Stupidity is not against TOS. If that was the case 70% people would be banned from internet.