Ecobank ATM Paid Me Counterfeit

 Were it from someone else I would have given reasons why it will be impossible for an atm machine to dispense counterfeit naira notes. But an atm machine in Omoku Rivers State after series of withdraws yesterday 19/2/15 dispensed a counterfeit #1000 note. It was a shocker. I immediately alerted the security men there, they advised I wait till 8am when the bank usually opens and all other witnesses around were filled with awe. Finally they opened their doors to customers around 8:30am I walked in and got a bigger surprise; the senior officer or operations manager said there's a possibility I had it on me that I should write a complaint and attach the note (story for the gods). So my dear good people of NL. How do I handle this? I still have the note with me. Lest I forget, there and then a security guard offered me #500 for that same note but I refused. My anger was the attitude of the customer relations officer and whoever the operations manager was for saying I had it on me. I had to collect phone numbers of people who witnessed the incident. So give me the best way to get them not to make such expensive mistake again.