ATM REDUCED MY MONEY

I WAS USED COMMMERCIAL BANK OF ETHIOPIA ATM ON 01/12/2013 ARROUND 6 OCLOCK AT SHASHAMANNE AT THE TIME ATM MACHINE DID NOT WORK PROPERLY IF I ASK 2 TIMES TO WITHDRAW 200 BIRR IT REDUCES 400 BIRR FROM MY ACCOUNT NOW SINCERERLLY I ASK YOU TO CREDIT MY BIRR NURADDIN IDRIS ASASA