After you block someone on Messenger, you can unblock them if you want them to be able to send messages to you again. read more
Good Day here is the complete guide with provided screenshots and more Facebook Contents that might help you a lot. below link will lead you how you can easily block and unblock users on Facebook messenger. read more
How to Unblock Someone on Facebook Messenger. Three Methods: iPhone and iPad Android Desktop Community Q&A. This wikiHow teaches you how to allow someone whom you've previously blocked to contact you using Facebook Messenger. read more