Government Officer harassing subordinate

Vice Principal (Head of School) in my school initially over burdened me with excess of work: Non Academic work of transfer of government subsidy into nearly 1600 students' bank accounts and full fledged Academic work. The work included many steps: opening of the bank account, then it's data entry online and offline, then CD preparation. As compared to any other teacher in the nearby government school. He assured me to grant Earned Leaves in my Service Book. Later when extra Academic work was about to finish he started to point out faults in my work and started issuing Memorandums. He issued Memorandum to resubmit the attendance for the days I was on statutory duty, whereas he himself had made me On Duty and rejoined me after taking proper orders. Before Memorandums he marked me as Absent in the Online Attendance and later he again marked it as Casual Leave, since I had sent it on WhatsApp. In the second Memorandum he pointed out that I was Absent and haven't submitted the application. Now after excess of work and torture I managed my class' absent Students Departmental Tests by conducting and evaluating myself. He is now objecting this. Whereas the Examination Cell of the school is in the lobby with him so I had to conduct exam myself. Now he is demanding written Apology to spare my Service Record. Else he is threatening to charge 120B, 418, 419, 420, 468 and 471. Regards and Thanks