Each marketing order and agreement shall prescribe the time, place, and method for payment and collection of assessments upon any uniform basis applicable alike to all producers subject to such assessment. For such purposes the Commission may take such action and means as provided by the order or agreement to collect such assessment. Unless otherwise provided in any marketing order or agreement, assessments payable by producers shall be paid prior to the time when the affected unit is shipped off the farm, and assessments payable to handlers shall be paid prior to the time when the affected units are received by or for the account of the first handler. No affected units shall be transported, sold, marketed or otherwise handled or disposed of until every due assessment has been paid and the receipt issued.