Regarding non payment of interest on pending salary

My father had been an employee of Biscomaun, Patna, For non-payment of pending salary he had filed a case and Patna high court gave judgment and directed Biscomaun to pay salary with 6℅interest upto the date of payment, In the meantime my father got retired and expired, later Biscomaun issued cheque for salary only in my mother's name, on demanding interest Biscomaun showed us a judgment which pardoned the interest payment, please let me know that, can a high court contradict it's own judgment when it has already ordered the proceeding in our favour. Moreover my father was also eligible for 5th pay scale which as on date has not been paid to any of the employee of Biscomaun(Bihar govt)