Sum Late Payment amount

I currently sum the total amount invoiced and the total amount paid per month. I need to add a formula to figure to out how much of the total amount paid is from old invoices, but not sure how to do this. (for ex - if an we paid $5000 this month, how much of the 5000 is from previous invoices)

These are the current formulas I use:

total amount invc'd = sumsifs(fees!$e$3:$e$5000,Fees!$c$3"$C$5000,">="&C5,Fees!$c$3:$c$3,"<="&D5)

Total amount pd = sumsifs(fees!$Fees!$E$3:$e$5000,Fees!$G$3:$G$5000">="&c5,Fees!$G$3:$G$5000,"<="&d5)

Column E is the amount invoiced
Column C is the date invoiced
Column G is the date pd

C5 is the 1st day of the mth
D5 is the last day of the mth

So column C contains both a list of invoice dates and the first day of the month in C5? Please upload a sample.