I can't log in to minecraft.net, what do I do?

Okay, so I can log in and play minecraft just fine, but I want to change my skin, and I went to minecraft.net and went to log-in, and it asked me a security question because i haven't logged in on this computer before. So I was like, "Okay, I know what my sister's middle name is." I put that in, says it's wrong, asks me for my Dad's middle name. So I'm like, "Okay, I know what my dad's middle name is." So I put that in and it still said it was wrong. I now have too many failed attempts for no reason and I can't change my skin. The frick, Mojang?