IT Payment

While making incometax payment, in many banks that too particularly in Indian Overseas Bank, they are entering the year of payment as assessment year and not the asessment year for which the tax was paid . for example if any one makes payment  on 30-3-2011  towards the assessment year 2009-10, the Bank enter the tax paid for the assessment year 2011-12. While refering the issue with the concerned Bank they are reluctant  to rectify the mistakes . What to do ? In my case tax  was paid on 30-3-2010 for the assessment year 2008-09. But while viewing the 26AS Statement, it clearly shows that for assessment year 2009-10 no tax was remitted  and for the assessment year 2010-2011 tax  was paid under self assessment.  Please let me know how to rectify the mistakes ? How to change the asssesssment year. ? In my challan the assessment year is very clearly specified. Even though the Banker is taking the year of payment as assessment year.