Quoted from "MegaMouseSEC;527184"
Ok on the bottom of the launcher there is an option to pick which Region you play on. Make sure that it is set to where you created the account for. If you signed up for the US servers it should say Region: a us flag then Language: enus.
Now if that is what is showing there is a possibility that you signed up on the EU website and you will need to change the Region setting for them. Just click The "Region/Languiage" button on the bottom right of the launcher between the start button and the exit button. Change it in a small popup that will have the options you need.
Make sure you change the Region/Language settings to where you are playing from and where you signed up from.