You Can try the following to rollback your transactions:
(It appears that you are seeing distributed transactions as Prepared instead of collecting.
Try running this:
SQL> select LOCAL_TRAN_ID,STATE from DBA_2PC_PENDING;
Then based on your results issue the following:
SQL> rollback force '
SQL> commit;
SQL> alter system set "_smu_debug_mode" = 4;
SQL> exec dbms_transaction.purge_lost_db_entry('
SQL> exit
You should repeat this for each entry that you get back from the first query.
Good luck.
Stacy