What should I do if the cat nests made for stray cats are always taken away by garbage collectors?

Me too! I really can’t stand it.

I suggest you get a wooden one and nail it directly to the wall or other place, or stick a piece of paper and write in big words “Cat Nest, please don’t take it away” with a colored pen. Kind of

(Actually, I don’t know if the person who took away your cat’s nest was intentional. If not, it’s fine. The one downstairs in my house was intentional. No matter what, they would take away the cat’s food bowl. )