Multiple pets?

Hello.
I tried having multiple pets but it doesn't seem to work?
Now I have 2 pets with names and equips rotting in the cashshop. What do I do? If they don't work can't I return them?

 

What do you mean it doesn't work?

 

I tried doing the pet snack quest but it doesn't seem to work when I reach the top and click on the bag.

 

Did you already accept the quest and given Bartos the pet snack? and nothing happens when you click the kittens basket at the top? Did you get a note?

 

I managed to do it, but the third pet is quite buggy.