Cant link my xbox live gamertag to my account

ok so i try and link my xbox live gamertag to my account. my gamer tag is HAMMER Pro, and every time i try it says it has bean taken and i dont have any other accounts so theres no way... if you have any info here is my email thehammer116@aol.com thanks|||did you link your gamertag on another email account? if you did that might be the problem i did this once and had to make a new email for my psn id, im not really sure if im right or not, could be