What would the OT do? Neighbors dog has fleas and they neglect it.

So nobody wants a wall of text. So I'll try to sum this up in a long, but condensed version.

1. Shithole neighbor doesnt take care of their dog ( doesn't feed it enough, flea treatment, or let it inside sometimes when it is hot or cold).

2. Dog start starts coming to our house. Runs inside and devours food every time. She ends up coming over regularly and sleeping at our house cause they dont let her in half the time. We notice ticks and fleas.

3. I talk to neighbors about her coming over hungry and they just say she eats too much, but the dog is normal to a little skinny. And she has stayed at our house at this point for weeks at a time and only eats about a bowl a day (normal for her size).

Times goes by...

4. She is basically living at our house at this point, we buy here a seresto flea collar and it clears up the flea and tick issue. I ask neighbors if we could "adopt" her. Their kitten has also started living at our house. They say we can have the cat, but not the dog.

About a year goes by with no big issues. Dog stays with us most of the time and just visits the neighbors...

5. Neighbors get a new puppy. Puppy gets infested with fleas. The dog that has come to live with us likes playing with the new puppy and spends more time there, but still comes to our house to eat and sleep when they forget or wont get up to let her in. New puppy wants to come over too, but I have to run her off cause we just cant have another.

6. Neighbors kids takes off flea collar right after I replaced it. Neighbor throws it away after I asked about it and they said they would put it back on her. I know cause neighbors kid told my son they did.

7. I buy frontline, but it doesnt seem to be working. She's probably just getting new fleas everytime she is around the grown puppy. I can't get her nexgard or something like that cause it requires a prescription and shes technically not mine.

I just had to stick her out in the cold after she ate cause I was getting bit by fleas from her on the couch. I feel so bad for her, but I don't know what else to do. She comes over daily to eat and usually stays the night. If I put her out, half the time they dont let her back in.