Pull invoices for customer statement

I am trying to create an Excel sheet to simplify customer statements. I have a drop down list to select the customer # that auto populates the customer name. I need to figure out how to auto pull all invoices from the database based on the customer selected. 

I also would like to figure out a way to add together the balance & payment amount based on the PO #. Each transaction is listed on a different line, but I would like to have everything for the same PO on one line for the statement (charges & credits cells).