bobessem, I am just letting you know that because you do not meet the requirements, T-Mobile will not unlock the phone for you. Your best bet is to try unlocking services that charge you a fee.
Also, with 521, you won't get 3G/4G in your country, just talk/text and 2G (GPRS/EDGE) data. So, I don't know if it is even worth it to try to unlock the phone.