The registration key wasn't accepted by their server (different hardware) and I was instructed to call their support line. After a brief time on hold, I was then subjected to about 10 minutes of up-selling and scripted 'intelligence gathering' ("[customer name] what is it your company does [customer name]?", "[customer name] what is your annual revenue?" "[customer name] we appreciate your business and would like to offer you [some crap-assed product] at a discount.")
After declining to answer all questions and (politely -- mentioning to the call centre staffer that I knew it wasn't their fault) asking for them to just give me the damn validation code for installation, I was then allowed to use the software I paid for.
It would have been easier to pirate the product, which is what I made clear to them in my (ignored) letter of complaint.
Idiocy.