Hi there meadowpaw_of_shadowclan,
We understand you'd like to receive messages from when your contact was blocked, and we'd like to see if we can assist.
Check out this article: Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch
Specifically, check out the details below:
"When you block a phone number or contact, they can still leave a voicemail, but you won't get a notification. Messages that are sent or received won't be delivered."
Since the messages aren't sent or delivered, there wouldn't be a way to receive messages that were attempted while the contact was blocked.
Regards.