.wordpress.com domain from .org

Hello,

so, for financial and organisational reasons, I need to transfer from a wordpress.org website with the address http://www.agglorouentransition.org to a wordpress.com website with the address http://www.agglorouentransition.wordpress.com.

– Before the .org address, I had actually created the wordpress.com address but upgraded it to a .org domain.
Now I want it back but wordpress.com would not allow it :/ I cannot find the password for that domain and my email won’t work…
==> How can I can to turn back to the wordpress.com with THAT exact domain address?

– Besides, I have tried many times to upgrade to WordPress 3.9.2 with the current wordpress.org website (www.agglorouentransition.org) and I get many error responses
(Fatal error: Cannot use object of type stdClass as array in /home/agglorou/www/wp-content/plugins/all-in-one-event-calendar/all-in-one-event-calendar.php on line 160)
I cannot manage to reach the Extension section as I (also) get that error message)

Thank you very much for your concern,
Julia