Neb. Rev. Stat. §§ 70-1304
If a purchaser of electricity at wholesale elects to dispute all or any portion of the wholesale electric charge established by the supplier, the purchaser shall nevertheless pay the full amount of the charge stated in the billing within the time established in section 70-1303 and shall give notice in writing to the supplier stating such election. The notice shall fully describe the basis for the dispute and set forth a detailed statement of disputed issues and the relief sought by the purchaser. Written notice of a dispute concerning a mathematical, metering, or quantity error in the billing shall be given by either party to the other within the time set forth in the power contract or, if no contract exists or no time is set forth in the contract, within sixty days after the discovery of the error.
Neb. Rev. Stat. §§ 70-1304