If you purchased Audit Defense, here is a contact link: http://www.taxaudit.com/turbo-tax-audit-defense.
You can also check out the TurboTax Audit Support Center. This is free even if you did not purchase Audit Defense. In addition to using our self-help tools, you can call and talk to a tax expert to assist you in more detail. The following link will take you there: https://support.turbotax.intuit.com/irs-notice/audit-support/.