ISSUE:
Whether a civil court has the jurisdiction to decide matters when a special law provides an alternate mechanism for resolving disputes?
Whether the remedies under a special statute, such as tax disputes under a tax law, bar civil courts from hearing related cases?
Whether sales tax collected under a statute imposing discriminatory taxes on inter-state trade is unconstitutional and refundable through a civil suit?
RULE:
Civil court jurisdiction is excluded if a statute expressly bars it and provides adequate remedies, except when statutory provisions are violated or remedies are inadequate.
Taxes violating constitutional provisions, such as Article 301 (freedom of trade and commerce) and not saved under Article 304(a) (equal taxation for inter-state and local goods), are unconstitutional and can be challenged.
Refund suits are maintainable where no statutory mechanism exists for refunding illegally collected taxes.