Does Decipher TextMessage Show Messages From Blocked Contacts?

Unfortunately, just like the iPhone Messages app, Decipher TextMessage does not show any messages that were sent while you had the sender blocked. Since the Messages app doesn't store the blocked texts, the blocked messages are not available to Decipher TextMessage.

Unblocking a contact will not cause the messages sent while he or she was blocked to be delivered to your iPhone. Only new messages will appear (as normal) when they are sent.