N.J. Stat. § 54:39A-19
Except with respect to payment of a special assessment imposed by the director pursuant to section 11 of P.L. 1963, c.44 (C.54:39A-11), or R.S. 54:49-5 or R.S. 54:49-7, a user, at any time within four years after payment of a tax, may file with the director a claim under oath for refund, in such form as the director may prescribe, stating the grounds therefor, but no claim for refund shall be permitted to be filed after proceedings on appeal have been commenced as provided in R.S. 54:49-18. If, upon examination of such claim for refund, it shall be determined by the director that there has been an overpayment of tax, the amount of such overpayment shall be credited against any liability of the user under this act and if there be no such liability, the user shall be entitled to a refund of the tax so overpaid. If the director shall reject the claim for refund in whole or in part, the director shall make an order accordingly and serve a notice upon the user. This section shall not apply to applications for refunds provided for under section 8 of P.L. 1963, c.44 (C.54:39A-8).
N.J.S. § 54:39A-19