original and was used. The CD key seemed to work but maybe I just need to buy a new copy
Yeah that'd be a warning sign. I don't think they are selling the original Sins by itself in stores now, so that could be the problem.
Your best bet is probably to email [email protected]. I wouldn't get your hopes up but they may shift the registration to your account if you provide the documentation they'll ask for. Note if this works you'll be eligible for a $10 discount on the newest and final expansion, Rebellion (note this offer may expire soon).
The other version of Sins still being sold is Trinity, but its only $19.99 and is occasionally on sale for less. If you can't get the registration transferred Rebellion just came out so its $39.99 without the discount. Rebellion has the most content, including everything in trinity, but it is twice as much.
