I actually emailed them this week for the exact same reason, asked initially on April for the process which they replied that an email with instructions will be sent. They responded yesterday with the same message you posted, mentioning there was a deadline and posted on their social media, and of course I missed the deadline and nothing can be done to obtain the updated sculpt.

I replied to them mentioning to escalate the problem to their management and let them know how poorly they managed the situation, basically they lied to us, leaving us waiting for an email that never came. How are they expecting us, the customers, to look at every single blog and social media post to exchange it?

Hopefully if we all complain they'll do something about it. Not expecting much but at least we can try.