For a long time, RS honoured the first come first serve and 1 order per person rules for ordering a Pi. I believe they still do as much as they're able to.
Perhaps there was a problem with your registration of interest or something else? We're aware that some users using gmail around that time (myself included) found emails from RS in their spam folder, which of course would be deleted after 30 days.
Have you tried contacting RS directly?
See also this thread
where some kind folks from RS are taking order queries.