In Cell B4 " 29 Jul 2016 "
In Cell A5 " {=SUM(IF(Table1[Due Date] >=$B$4,SUMIF(Table1[Due Date],">="&$B$4,Table1[Payment]),0),B5)} "
In Cell B5 " {=IF(Table1[Due Date] <=DATE(YEAR(B4),MONTH(B4),DAY(B4+14)),SUMIF(Table1[Due Date],"<="&DATE(YEAR(B4),MONTH(B4),DAY(B4+14)),Table1[Payment]),0)} "...