Collision with cloth not working,Cloth component not working

Hello Guys,

I'm trying to do something like this : https://www.youtube.com/watch?v=3bEoNQ82ePY.

I have a cloth component in the form of a spherical mesh. I dynamically add sphere colliders which move "randomly" inside of the mesh. The behaviour I expect is that each time one of these spheres collides with the cloth, the cloth will be deformed just like in the above link.

The spheres colliders shouldn't get out of the cloth, but just deform it. You'll find some screenshots below are some screen shots. Thanks in advance guys.