Asking for a refund

[smitus-yceoc]

A couple of weeks ago I sold an access code for an online textbook at vital source. Today I get an email from the buyer demanding a refund stating that he never knew it was an online book Even though I messaged him with the access code and how to redeem it at the website and he emailed back. My question is do I give him the refund knowing that he could have possibly redeemed the code already. 

[chrysylys]

Yes, you need to refund in full since you're not supposed to sell those here, or probably not at all.  Have you checked with the publisher to see if they permit their codes to be sold?  Most do not.