Here is an additional point regarding refunds.

If you have a merchant account and make refunding difficult you will end up with high chargebacks and lose your ability to process credit cards.

Customers that either don't recognize the text phrase on their statement or have trouble finding the customer service number or email address for requesting refunds will simply call their bank. The bank will charge you back and, although, you have the ability to fight it, even if you win and the bank reverses the chargeback that chargeback (complaint) statistic remains on your record.

If you sell a good product or service that delivers the claims that you make the vast majority of customers will never request a refund or charge you back. If, however, you don't deliver, then maybe you shouldn't be selling that product/service.