The red flag for me here is that they didn't even try to work anything out with you. They received the items and then just immediately demanded a refund. That's kind of weird.
That said, I would take the items back, expecting them to pay shipping, and refund minus the deposit (I'm assuming you made sure to show them the TOS, point them to it again if necessary), and then try to sell them elsewhere if I were unable to fix/change them to the customer's liking.
I don't think you're going to get out of this one without making the customer upset unless you surrender all the money to a full refund, though, but I don't think they're entitled to a full refund in this particular case, especially since they made no attempt to compromise first and it doesn't sound like the items were damaged or anything. You're going to have to go into it expecting them to be angry while standing your ground.
no subject
That said, I would take the items back, expecting them to pay shipping, and refund minus the deposit (I'm assuming you made sure to show them the TOS, point them to it again if necessary), and then try to sell them elsewhere if I were unable to fix/change them to the customer's liking.
I don't think you're going to get out of this one without making the customer upset unless you surrender all the money to a full refund, though, but I don't think they're entitled to a full refund in this particular case, especially since they made no attempt to compromise first and it doesn't sound like the items were damaged or anything. You're going to have to go into it expecting them to be angry while standing your ground.