Tax notice due to wrong Pan card detail

I am a semi government teacher and for this financial year/(2016-17) applied for refund(My oral cancer detected in feb 16 and operated on mar 16 so applied refund due to deduction under 80DDB). I got a mail from income tax department yesterday that there was some due on previous years so my refund will adjust if i'll not reply within 30 days. When i check attachment then they calculated tax for financial year 2010-11,2012-13 and 2013-14. In every year tax already deducted from my salary and i filled ITR. On these mentioned financial year i filled ITR manually not online. I got only one receiving for financial year 2010-11 in which by mistake i write wrong Pan Card number.My pan card is A%%%%%%%%L but i write A%%%%%%%%I so instead of L i write I. So i think for mentioned three financial year i did same mistake. In form 26AS tax information is already showing for each year it means already i given tax money to tax department every year. Now please guide what can i do and to whom should i contact. I am a cancer patient so not able to go income tax office. Should i make any online request to income tax office. I've not get any information regarding this earlier from income tax department.