Processing return and exchange requests takes between 2 to 3 business days.
If you’re looking for an exchange, you can expect to get your new item delivered between 3 to 7 business days after processing.
If you’re worried about a refund, keep in mind that these can take up to 5 days to show up in your bank or credit card statement after issued. Some banks also prefer to issue them during the next billing cycle - getting in touch with your bank or card issuer in this case is a good idea.
See also: I was issued a refund and haven’t gotten it yet. What’s happening?