i'm not sure if this belongs to portals. I have a simple FM DB to keep track of my patients lab tests. I need to keep track of what each patient pays for his lab tests, for example:

NAME-------Date---Amount Due--Payment--Balance

John Doe--1/10/09----$100------$70------$30

------------1/13/09----------------$30------$0

------------2/1/09------$120------$100-----$20

------------2/5/09-----------------$20------$0

Maybe this might give you an idea. Or it may confuse you even more.

http://starrdata.com/Payments_System.pdf

You are right. I'm confused further more. I hope that there is a simple way to do it. If not, then I will need your guidance.

Try this, go here StarrData Downloads

Download the SubSummarry Report demo.

The data is old but it tracks how much is still owed by custom and invoice 30/45/60/90 days