The debtors filed this adversary proceeding to stop the IRS's post-discharge collection of pre-petition taxes that the debtors believed were paid through the Chapter 13 plan. The court granted summary judgment to the IRS because the taxes arose from late-filed returns and were not dischargeable under §§ 1328(a)(2) and 523(a)(1)(B)(ii). The debtors had miscalculated the amount due when they objected to the IRS's claim; because the IRS was not properly served with notice of the objection, it did not oppose the objection. Regardless of the notice issue, the debt was not discharged and the IRS did not violate the discharge injunction in renewing its collection efforts.