Any organization or entity exempt from the tax imposed by this chapter, or imposed pursuant to the authority granted in § 58.1-605 or § 58.1-606, that knows or should have known that an associate, employee, volunteer, other individual or entity has used its tax exemption certificate/letter to make unlawful purchases in the aggregate in excess of $1,000 in any calendar year, shall have its tax exemption suspended in accordance with § 58.1-623.1.