One even went so far as showing a Western Union invoice.

Does it help with invoicing or processing payments?

I have a hard file filing cabinet that invoices, manuals, other documents go into by year and property.

I put the X-NUMBER on the line on the bank statement, on the copy of the check that was written and on the invoice, contract or document that coincides with both the transaction and X-NUMBER.

Problem is, most PMC's do NOT share the contractor or material invoices, they just send their own invoice.

- who draws up the papers for owner financing terms and invoices?

It's not "harassment" to send them a final invoice just like you would send them a refund if they had anything left over.You could take them to court, seek a judgment, and then send it to collections if they still refused to pay.

These have saved me thousands of dollars over the years.The aversion on here of doing anything on your own is pretty dang pathetic. 

 If I need to send a certified letter with a lot of paperwrk,to a tenant who moved out  an wont give new adress ,can they use a lawyer to receive these documents .It confirms the $ an invoice of cost deducted from security deposit   ..Tenant wont give adress ..but will give  a lawyers .Thanks It's in tn

Maybe ask him for an itemized invoice so you can compare his costs to what you find them to be.