Hi Arpit,
Are you sure if you still have orders ? Have you checked it in RRP3, ideally the FA category orders should be deleted using the RLCDELETE. In case you still have the order as suggested by other try using md74 which is re-org. If this doesn't, try and get the GUID number for all these orders which you can by using GT_IO and later you can delete them by using the program /sapapo/om_delete_incon_orders program.
Regards
Sasi