When u commentaar on a profiel wall, the fan whose profiel it is always gets a message in his of her updates about it, but obviously they sometimes don't reply. When u commentaar on a club wall, only people who choose to look at the uithangbord section see it (I think the same is true for personal clubs).
Yep. I sometimes forget to check my uithangbord and see a commentaar only after few days. If u need to reach someone, u can try writing on uithangbord and also pm them