Ind. Code § 6-8.1-9.5-6

Sec. 6. A debtor who receives written notice pursuant to section 5 of this chapter is entitled to contest the claimant agency's right to the debt and set off at a hearing only if the debtor, not later than thirty (30) days after the date the written notice was mailed to the debtor, mails to the claimant agency written notice that the debtor intends to contest the claimant agency's right to the debt.