[Koha] urgent please

hi     i am using koha 2.2.8 i have problem in issuing rules. after due date fine is not working. i enter issue/fine field this patron.  14,2/5.0   its mean only two books issue for 14 days and Rs.5.0 will be fine per day after 14 days. but its not working. please help me i am witting for your great responce.thanks.