Tax Problem due to salary arrear

I work as a teacher in delhi government. I joined School A- In the year 2022 I didn’t received my 3 month salary - Aug, Sep and Oct. But when calculating total gross income for tax purpose, school included the amount of these unpaid salaries. Even in the form 16 it was included. Now coming to year 2023. I transfered to school B.I received the salary as arrear (Aug Sep Oct 2022)in the month of July 2023 (From previous school). Now when tax is being calculated this salary amount is showing in my gross income. I asked my school that it was included in last financial year but they are saying - you have received this financial year so it will be included. The amount is 2 lakh which is increasing my tax slab. I tried to convince but they have included the salary arrear amount in this finacial year. I am stuck how can this same amount can be included in two financial years. In year 2022 even including this amount i had to pay 0 tax. That was beneficial. Even if i put back salary arearr to previous year ( form89 and 10e) then it is problem as it has already included. Please Guide