An Indianapolis tax preparation business at the center of a Call 6 investigation said it is taking action to review 2,000 returns that were possibly filed under fraudulent pretenses.Prime Time Tax Services, at 5415 W. 34th St., offered "24-hour checks and the best refunds in the country."A tip about long lines outside the office led RTV6 to investigate why so many people were going there and why many were convinced the tax preparer would get them larger refunds. Call 6 Investigator Rafael Sanchez found that a couple of Prime Time clients have received a two-page letter from the Internal Revenue Service that says, in part, "We have received your income tax return and are holding your refund until we complete a thorough review of your return."Customers gave RTV6 evidence that they showed Prime Time Tax Services was giving customers with young children college tax credits they didn't deserve.Nahtanha Perez Martinez was one of the customers."I was thinking maybe they'll be able to find me an extra $100, or something, but $13,000 (was the amount of the refund), and that is double what I usually get, Martinez said.Meanwhile, Call 6 investigators also uncovered records from the Indiana Department of Revenue about Omega Chatyoka, the wife of Prime Time's owner.According to state documents, Chatyoka is the target of an outstanding tax warrant and owes more than $1,000 in unpaid income taxes.Robert Cheeseborough, the attorney for Prime Time, confirmed that the IRS criminal investigators have visited the business from 2010 to 2011.Cheeseborough said the business has hired an accounting firm to review the returns at no additional cost to its customers.The business is now closed until all accountants have completed their review.Customers who received refunds with the college tax credit will need to file an amended return because the IRS will demand repayment, officials said.