Unclaimed refunds totaling more than $7 million are awaiting more than 6,000 Maine taxpayers who failed to file an income tax return for 2001, the Internal Revenue Service has announced. In order to collect the money, a return must be filed with an IRS office no later than April 15, 2005. The IRS estimates that half of those who could claim refunds would receive more than $440. In some cases, individuals had taxes withheld from their wages, or made payments against their taxes out of self-employed earnings, but had too little income to require filing a tax return. Some taxpayers might also be eligible for the refundable Earned Income Tax Credit. “If you don’t file a return, you can’t get a refund,” said IRS Commissioner Mark W. Everson.