BSNL Chennai Telephones — monthly bill shows less amount

My telephone -landline- number is [protected]. I paid online Rs 210/for safe custody for 3months with effect from 28th July 2014.This amount was detected from my monthly June 2014 bill. I paid the reduced amount as shown in the bill.If my phone is under safe custody I must get nil amount bill for the month of July 2014.Please correct the error if any done in the bill.