This story had a couple funny moments, but overall it wasn't as funny as it seemed to think it was. And even in a funny story I still generally want something to happen.
I was interested in the beginning, and was amused with much of the conversation with the aliens that revealed the mixup--the listing of tropes was funny. But then the story kept on going, and seemed to forget the humor after that point, finishing up at an off-note wish fulfillment ending that didn't really seem to match the rest at all.
I find it completely hard to believe that an alien race that studied us by the means of the Internet would not have incorporated porn. I realize that would've been harder to write into a story while keeping it readable and clean enough to publish most places, but still it was a huge hole in the core premise. I probably would've overlooked that if it had been more consistently funny.
So the plot goes:
Cats are replaced with something weird.
It turns out aliens did it with good intentions, oops!
Aliens very nicely reverse their mistake.
Also, long life for pets, yay!
The End.
(I think it could've been nice to have some actual conflict)
The main character said repeatedly that she was distraught, but never actually sounded distraught, she just sounded annoyed that her daughter was making a fuss.
Don't get me wrong about the wish fulfillment ending--I would probably use that technology. All 3 of my dogs are under that weight. On the other hand, that would mean that more strays would probably be euthanized because anyone who is inclined to have small animals would just prolong those animals. But in any case, it wasn't a funny ending and didn't really fit with the rest of the story.