Hi there - one of our Happiness Engineers responded to you by email on January 24, but it sounds like you didn't receive it.
Your domain, plantandoumasemente.com, expired on September 10, 2012 and unfortunately someone else purchased it on November 28, 2012.
As much as we'd like to help, there's nothing anyone can do. Once a domain expires it's in the hands of the registrar and can be sold to someone else, which is what happened here.
Since you no longer own the domain, I removed the domain mapping for that domain off your account so you can access your blog at http://plantandoumasemente.wordpress.com again.
Please let us know if you have further questions.