Communication on arrear demand intimation u/s 245

I got a mail from CPC demanding Rs. 14082 arrear for the AT 2007-2008. 

As per the original returns, I suppose to get Rs. 5000+ as refund. But due to incorrect MICR number the refund process was stopped. But, during this time I have wrongly filed the returns of AY 2008-2009 to the year AY 2007-2008 through online.
The IT depatment have taken cumlative of both returns in AY 2007-2008 and send me the demand letter.

Many times, I approached them(AO) and explained the problem and also given in writting ( + form 16 of both AY, demand letter, ITR acklment) . But seems like nothing was considered and they keep sending the arrear demand for the AY 2007-2008.

Hope I explained clearly. 

I am helpless now and I do not know what to do. Please help me regarding this.

Thanks,

Sakthi

Rectifiction u/s sec 154

Even i tried to submit rectification u/s 154, it asks cpc commuication ref. number. I do not have that, becoz for AY 2007-2008 i hav not filed through online.