It sounds like the guy, though a bit incredulous, was asking an honest question. Your response seems a bit heavy-handed, especially when viewed in the light of a public forum.
However "unreasonable" the $395 might seem to the rest of us DIY, the response has left a bad taste in all our mouths, even if we are not privy to all the details.
Was the license non-transferable or restricted? Not sure of the details (again, our perspective here is limited, and perhaps a bit biased), but defensiveness comes off as a cover-up, even if the customer is/was unreasonable/unaware of the amount of time it requires from your company (trying to maintain a semblance of profitability) to look up, transfer, record, etc. the "new" key.
We're all in this together, even if we think we are on opposite sides.