How can I recover my disappeared iMessage conversation?

I deleted and muted a conversation today on iMessage. When I sent to go see if I got a text I saw that the person texted and I swiped out of the message then I go back into iMessage the text was gone. I recovered the message and I still can’t get the message they sent me back.Why did this happen how can I get the message back

[Re-Titled by Moderator]

Original Title: iMessage problem