On August 16, Frederick Ognibene went to the ATM area at a Citibank branch and activated one of the machines with his Citibank card, provided his personal identification code, and withdrew $20. When he approached the machine a person was using the customer service telephone located between two ATM machines and appeared to be telling customer service that one of the machines was malfunctioning. As Ognibene was making his withdrawal, the person said into the telephone, "I'll see if his card works in my machine." He then asked Ognibene if he could use his card to see if the other machine was working. Ognibene handed his card to him and saw him insert it into the adjoining machine at least two times while saying into the telephone, "Yes, it seems to be working." When Ognibene received his Citibank statement, it showed that two withdrawals of $200 each from his account were made at 5:42 pm and 5:43 pm, respectively, on August 16. His own $20 withdrawal was made at 5:41 pm. At the time, Ognibene was unaware that any withdrawals from his account were being made from the adjoining machine. Ognibene sought to have his account recredited for $400, claiming that the withdrawals had been unauthorized. Citibank had been aware for some time of a scam being perpetrated against its customers by persons who observed the customer inserting his personal identification number into an ATM and then obtained access to the customer's ATM card in the same manner as Ognibene's card was obtained. After learning about the scam, Citibank posted signs in ATM areas containing a red circle approximately 21⁄2 inches in diameter in which was written "Do Not Let Your Citicard Be Used For Any Transaction But Your Own." Was Citibank required under the Electronic Fund Transfer Act to recredit Ognibene's account on the grounds that the withdrawal of the $400 was unauthorized?