I had a few options. One, I could just ignore it- but someone did spend $50 (I think it was $50) to buy it and it would therefore be wasted. Two, I could use it myself (so the money would not be wasted) although that felt pretty dishonest (for obvious reasons). Three, it was a shot in the dark but I thought maybe the retailer would be able to refund the person's money due to the error.
I went with option three and contacted the retailer via email. Customer service responded a few days later asking for the certificate, which I then supplied them with.
About a week later, I was contacted again with an update from the retailer.. they were working on tracking down the original purchaser to work out a refund. Well that's good I thought.. and figured that was the end of it.
Over a month later, I received this email..
"We have contacted the customer who had purchased this item and let them know to contact us and we could forward them or the recipient the gift e-mail at an alternate address. Thank you again for bringing this to our attention. We value your honesty and have included a code for $25 for an online purchase below. The code is case sensitive and is not valid for tax or shipping costs. Thank you again for your assistance in this matter."
See that? My honesty was valued!