Hi Carla,
If the item wasn't custom, then I would agree with everyone above. As long as the item is returned to me promptly (within 30 business days from purchase date... which given my shipping times, is just over a month from when they should receive it), then I will refund the price plus/minus shipping depending on the situation (i.e. if they made the mistake, I will not refund shipping but if it was my error, then I refund the whole amount).
However, given that this item is custom - I don't think any returns should be accepted at all. Not sure if you have this in your policy, but for me, custom items are not resalable to someone else so for that reason, I make sure to give the customer as clear of an image of what they're about to receive without committing much time making it yet until it's approved. If I do everything they asked for and approved, and they don't end up wanting it after getting it, then that is the only time I say 'tough beans' (but in better words haha).