Name changing problem

Hello!

there seems to be an issue with the changing of usernames on minecraft.net.            basically it won't let me change to a few names. I'm making sure it doesn't contain any symbols or bad words. I always check if a username is open before changing but it still says "this username is not available". I also tried making a three letter username (that is not taken) with purchasing a brand new account, but it keeps saying it has to be at least 3 letters. I didn't find any problems on the Mojang website before, but now I'm not able to use it anymore, because it takes me directly to Minecraft's website instead. The best thing with the old version of name changing, was that you could check the availability.                               Hopefully it's something that I haven't recognize when changing my username that I can do different, but I am positive I have tried everything. 

-Yknow