Which version are you using of Express Invoice? I am on 3.99.
Are you referring to the invoice list instead of the invoice report? And the payments list instead of the payments report?
Have the payments been for invoices that are not necessarily the oldest ones?
I have found my version of Express Invoice to be very persnickety about which invoice a payment applies when I try to apply it to a more recent one if there are still older ones on the books. When you apply the payment, watch to see how much of it is applying to which invoice. You can change those applied amounts in that screen. Working in the main computer, I have found that I have to double click on the "Apply Payment to Invoice" bar, making sure the correct invoices are highlighted. Then click OK. Double check to see where it applied in your invoices list. If it did it wrong, you have to go back to payments, delete that payment, and do it again.
Hope this helps!
Teri