Indiana Code Title 6. Taxation § 6-2.5-9-10

Sec. 10. (a) A taxpayer complying with IC 6-2.5-2-1(d), voluntarily or otherwise, may seek only a refund under IC 6-8.1-9 of taxes, interest, and penalties that have been paid to and collected by the department.  However, a refund may not be granted on the basis that the taxpayer lacked a physical presence in Indiana and complied with IC 6-2.5-2-1(d) voluntarily.

(b) IC 6-2.5-2-1(d), section 9 of this chapter, and this section do not limit the ability of any taxpayer to obtain a refund for any other reason, including a mistake of fact or mathematical miscalculation of the applicable tax.

(c) A retail merchant that remits gross retail tax voluntarily or otherwise under IC 6-2.5-2-1(d) is not liable to a purchaser who claims that the sales tax has been overcollected if IC 6-2.5-2-1(d) is later found unlawful.

(d) IC 6-2.5-2-1(d) does not affect the obligation of any purchaser to remit use tax as required under IC 6-2.5-3.