A Boston woman says she was scammed out of thousands of dollars by a man who claimed to be helping her at an automated teller machine.Megan Bates said Friday afternoon she decided to take out cash for lunch from a walk-up Bank of America ATM.Bates said that about ten seconds after she started walking away from the ATM following her withdrawal, a man called her over to the machine. According to Bates, the man said there was still money in the ATM's cash dispenser slot and she saw a $10 bill sticking out of it. She also said the man stated there was something wrong with the ATM and pointed out a blinking red light on the machine."He said: 'Give me your card,' and he took my card out of my hand and put it in the machine. He's like: 'Put your PIN number in.' He's like: 'You have to close the transaction because it's still open,'" Bates said. "It happened so fast, I didn't even really think about it."Bates thought the man was being very nice by trying to help her out until the next day when she looked at her bank statement and saw three withdrawals of $4,000 each had been made from her account.According to Bates, one withdrawal was made from the Bank of America at 60 State St., which is across from City Hall, and the other two were made from a Hanover Street location in the North End.Bates later realized that the debit card she had in her pocket was not her own, but a card that belonged to someone named Victor."Somehow, between when the card came out (of the ATM) again, he switched the cards," Bates said. "I don't even know how he did it. Sleight of hand? I mean, the guy was a magician."Bates reported what happened to the Boston Police Department and Bank of America, but she said she is left wondering how this could have happened because she said she has safeguards in place that prevent ATM withdrawals of more than $500 being made from her account at one time."It's frustrating to me that they can't tell me why this happened, like why someone was able to withdraw that much money out of my account in one day," Bates said.Bank of America told sister station NewsCenter 5 that this is a possible case of identity theft because the scammer made the withdrawals through a teller.Bates said the scam has left her in disbelief."You feel really violated, right? That someone can suck you in," she said. "I fell for it. I don't know why I fell for it."Bates said she is very embarrassed about what happened to her, but she spoke with sister station NewsCenter 5 in hopes of raising awareness of ATM scams so that something like this does not happen to anyone else.