If I except bitcoin on my online store, and a customer buys a product. What happens after 20 days and they want a refund in bitcoin? If bitcoin has gone higher or lower during that time, how do you figure out the refund amount?
Why do you ask us? This is a business decision you need to make for your self. If you are going to offer a refund it should be at the rate of the time of purchase. But obviously that could cost you more 20 days later. The best thing to is to fully live in Bitcoin, rather than living in a fiat world but saving you support Bitcoin.
Have you had this problem yet? You might be wasting time on an issue that doesn't really exist.
By the way, the word to describe your willingness to agree with or take on something specific is "accept"....not "except". Except actually means the opposite.