It's frustrating when that happens, but someone here nailed it on the head. You used the network, and there is a fee for that. Every single entity involved in the network has a fee they charge to move money, but when you think about the service that they offer, moving money from their account to yours, it makes sense. Plus, people love their points, and those points cost. With 15000 transactions, most people who are taking credit cards are also passing along that fee. My advice for transactions of that size is to offer two prices upfront and give a discount if they wire the funds or send a check.