<human>: Sorry for the length of this post!

A family that lives across the street bought a puppy around the same time as I brought home Willow. At first the dog annoyed me: they left her outside on a tie day and night and of course the dog cried all the time. After reading a few posts about neighbors with barking dogs on doggit, I decided to introduce myself. Willow and their black lab got along great. They were around the same size and played well together. 

I leaned that the this was the family's first dog and that they bought the dog off craigslist. I slowly gave them advice on crate training indoors, the dangers of unsupervised tie-outs, and potty training. I didn't want to seem pushy, so the advice was very short and spread out between playdates. Willow and I would frequently go over and play with the puppy and the three daughters. 

Last weekend, we went to visit my parents. When we came home, I no longer heard the puppy barking and assumed that they had started crate training inside. I kept an eye out for the puppy, so I could bring Willow over to play, but I never saw her. Plenty of times the daughters were out playing, but not with the puppy. 

I started to worry and today my fears were confirmed. I went over to ask if the puppy could come out and play. The family told me that they had given up the puppy to a shelter because it was too much work. The loss of this puppy really hit me. I am sad that Willow lost a playmate and sad for fear and confusion the puppy must be feeling. I am frustrated that another puppy mill received a profit and another dog is in a shelter. I feel guilty for not being more pushy and trying to help the family more. 

I know there was only so much that I could have done. I just feel so sad for the puppy and wish I could have changed things.

Can you condense the text into three sentences or less?
<bot>: Neighbors bought a dog off craigslist, becomes friends with my dogs, neighbors can't handle the dog and surrender it to a shelter.