Unfortunately this is just the way it works. You change it, then they change it back, rinse and repeat.
What I have found to work is to keep changing it until you hit 10 to 12 times. Then submit a redressal explaining how many times you entered the correct business name and they changed it to include spammy keywords. I also include a screenshot taken from my Gmail email account showing all of the times that you fixed their name to the correct name and the change was accepted. If you search in Gmail for their business name it should come up showing all the of those emails in a nice list with the date and their business name in the subject line saying that the change was approved. This has worked for me to get listings removed completely. But it takes time and a long history of them changing the name back.
Edit: I just changed his name to the appropriate business name and my change was published. I apologize that anyone else reading this won’t be able to see how spammy his name was if they click on your link.