hy, hair collision is not implemented yet, i think.
you can workaround with one or more forcefields (type: force)
check the maximum value of your forcefield, it has to be > 0
you have to try high strength (100-1000) values and maybe raise the flow value as well.
And the segments-value you find in the particle-propertys at the top of your hair particle system
and under “render” ind the same panel there is also a value (“steps” i think)
I have the same problem. My hair doesn’t collides with objects - just passes through them.
BUT! In Sintel Lite Rig hair dynamic. And it seems like hair collides with it’s proxies. I can’t repeat this trick