If you sent the incorrect item, I would explain that "no returns" doesn't apply when there is an error in the order or faulty items, and that they are entitled to a refund or exchange.

I forgot to add that if the wrong item was sent and it gets sorted out quickly etc, you can ask your buyer if they will agree to revise the negative.

Although for $4, there would probably be a number of sellers who would just refund in full regardless and request the revision.