interest charged on overdue sales invoices

Hi 

Can anyone help me with trying to find in Accountright the interest charges which have been calculated on an overdue invoice when a statement has been issued.

I have a client who has had several late payments on quarterly invoices and when i have emailed the statement they say they have never received it, so therefor i am unable to show proof of these charges as i can not recover the statements sent from last year.

They are now asking for statements but i am ubale to print or email these as the accounts are paid in full, but i still have outstanding interest charges!

This is very frustrating that i am unable to supply the charges from last year.