The IRS will not tell you if anyone has claimed her. If you can claim your child, then file a tax return that claims her in MY INFO. If you think maybe your parents claimed her-----try asking them. What reason do you have to suspect that your parents may have claimed your child? Did she live with them? Did they support her?
Did you file tax returns for those years that were rejected for duplicate use of the child's Social Security number?
Did you have taxable income to enter on tax returns for those years? Were you the custodial parent?