Airtel — regarding adjustment of pending amount of Rs.37 in my next bill.

I requested that i convert my airtel lite plan into P.W.D PLAN .I clear my all the dues. i.e unbilled amount till(i.e april 22, 2009 ) that date under the customer account no.[protected] of mobile no.[protected].But my paid amount is more (Rs.37) than of that of my bill. piease adjust my more Rs.37 in my next bill of my mobile no.[protected].