(a) the petition shall be presented within 21 days after the return made by the returning officer of the member to whose election the petition relates, unless it concerns an allegation of corrupt practices upon the making of the return of election and specifically alleges a payment of money or other reward to have been made by any member, or on his or her account, or with his or her privity, since the time of such return, under or in furtherance of such corrupt practices, in which case the petition may be presented at any time within 28 days after the date of such payment;