Companies, like Ultimaker, has outsourced their accounting. They do the accounting work propably once a month. It is bit different if company has financial department of their own. At least in Finland, accounting companies also charges per invoice. That cost is easily 2,5 euros each, which is something like 3,5 dollars. I asked for refund also at the spring because I noticed three days after placing an order that I can get UM2 from London in 5 days instead of 10 weeks. I got the refund after a month or so. But if customer f..k's up the order, it is not company's fault. Refunding causes also extra costs and Ultimaker didn't charge them from me. So, I think that I got good service. Not very fast, but good.
Ilkka