No minecraft username working?

So I went to finally buy myself minecraft and I went to enter the username I wanted. It was taken, which was disappointing so I thought I'd try some variations and maybe some completely different things. None of them worked. I was getting pretty frustrated and started keyboard mashing in some usernames, they all still showed up as taken! So, my question is basically why is this haooening? I checked the rules of making a username, the # of characters and all that, and everything I typed fit. I'm getting so frustrated, and help would be so appreciated.