[78-L] How do I charge zero?

[David Lennick]

Okay, someone has overpaid me on shipping for eBay 4 items and ordered two 
more. He paid for each item instantly instead of waiting for a combined invoice 
on the first 4. How do I send him a zero invoice (zero on shipping and zero on 
the two items)? Listing a discount works only on tax, shipping or insurance 
costs. Or do I just not invoice him, since we're even?

dl