Please note, the terms "24 Volt" and "28 Volt" in product descriptions are used interchangeably. Both refer to vehicles with two 12 volt batteries connected in series, or, four 12 volt batteries connected in series/parallel.
Alternators, generators, and starter motors are sold as-is and are not returnable, exchangeable, or refundable due to the wide variety of circumstances parts may be subjected to. No exceptions.
Alternators and generators are not supplied with pulleys. You must reuse the pulley from your existing unit.