Arrear of demand notice

recently, i have been receiving arrears of demand notice from CPC Bangalore.

the demands is as old as of of A/Y 2001 and onwards. Also the amount is like Rs 2 or 15.

In some cases, the amount of refunds are termed as demands.

whether it is justifiable??

also the notice of demand only states the amount of demand, it doesnt clarify any reasons for that demand.

what should i do now?