I already tried to contact support a week ago, but apart from an immediate autoreply ("this case has been assigned the code 'issue-57208'") I didn't get any answer 'till now.
What happened so far:
I preordered Jurassic Park back in December 2010.
In April 2011 I was offered a full refund, because the release was delayed.
I haven't claimed that refund yet (assuming I could still use it as credit when buying other Telltale games).
Now I'd like to order Jurassic Park again; can I convert that (yet unclaimed) refund to a shop credit (or use it in a similar way) to pay for the game?