Airtel — Misplacing cheques twice

The Airtel (Dehradun) Ottrakhand called me over phone to hand over the cheque of post paid bill of Rs 745 for the previos month through their Representaive who was visiting my Office on 31Jan,2008.The Representative named Munish collected the Cheque in person .Afer a lapse of 15 days again a call from the Airtel cenre came that we are retiving the Cheque as misplaced ,kindly give one more cheque towards the payment of Rs745/-they did not even bothered to locate the same but asked me to come with the bank statements .If my cheque has been misplaced then why should I send the statements for the fault of Airtel. This has happended for many times.