lenamihailova on "how can I return my domain back?"

Hi folks, couple of days ago Ive changed my domain by linking with design-cheloveka.kiev.ua. Now I just want to returne to my classic free blog domain lenamihailova.wordpress.com. No refund. But I just messed up with parametres and when I put lenamihailova.wordpress.com into brouser, I seeThe address design-cheloveka.wordpress.com cannot be registered. Only lowercase letters and numbers allowed. But you can sign up and choose another one`. I do not want to register anything new, I just want to go back to where I started with lenamihailova.wordpress.com. Can you help me with that?
Blog url: http://lenamihailova.wordpress.com/