How do I find Chinese manufacturers on Alibaba that will agree to modify their product and make a custom design?

I'm trying to find manufacturers on Alibaba that can manufacture a cat scratch post with a unique design.

The design really isn't out of the ordinary or overly complex at all (Thing a cactus cat scratch post or an Eggplant cat scratch post.... honestly it's probably a simpler design than either of those).

I've messaged ~15 manufacturers of cat scratch posts on Alibaba using the "chat" feature, including a generated photo of my design with some basic specs & also saying that I'm open to their recommendations.

All of them have simply said "No, we cannot modify our design."