Dozens of credit unions and banks were forced to shut down credit and debit card accounts after computer hackers gained access to millions of accounts at a major east coast wholesale chain. The company, identified as BJ's Wholesale Club, said a small number of their eight-million customer accounts had been accessed and it notified the major credit card companies, Visa and MasterCard. Both Visa and MasterCard then sent out alerts to their members. The security breach was causing havoc at several credit unions. Officials at Finger Lakes FCU, in Geneva, N.Y., said it shut down all of its 1,000 Visa credit/debit accounts as a precaution, even though there had been no signs of unauthorized use of the cards. "We'll issue members new cards immediately," said Ann Olney, vice president of Finger Lakes. "It's just a precaution." Family First CU, in Rochester, also said it closed down affected member accounts and issued new cards for the accounts.