I can't change my skin

I can't change my skin, they does not give me anything, I try to change him and he does not leave me but I do not get any message I have the same skin that the last time (name: Whaxy) and when I change the name (Whaxy) to (Sadowe) I can change the skin, but again I have changed THE NAME again sadowe to Whaxy. And now I can't change them in one server Minecochia(Youcochia)