Keep in mind that once the message sends, the other person can see it. When you delete a message in Messenger, you only delete it for yourself. The other party can still see it. But you can overcome this by unsending a message.
Your previous messages between yourself and the person you're blocking won't be deleted, so you have to manually delete those messages if you don't want them.
Deleting a messagepermanently removes it from your Chat list. Keep in mind that deleting a message or conversation from your Chats list won't delete it from the Chats list of the person you chatted with.
When you block someone's Facebook profile on Messenger, it also blocks their profile on Facebook. They won't be able to message, call or find your Facebook profile. If you're Facebook friends, blocking them also unfriends them. Profiles won't be notified when you block them.
If you block someone on Facebook or Messenger, you both will not be able to see each others activities and also not be able to send messages. Old conversation will be still in inbox but name of that person will not be clickable. See the Help Center to understand blocking: What is blocking?
Android phones move all blocked messages into a folder on the phone called “Spam and Blocked.” That means that the phone is still collecting messages from the blocked people; they just aren't notifying you.
A filled-in blue circle next to your message means that your message was delivered. And, when a friend has read your message, a small version of your friend's photo will appear next to your message. Jessica Mercado and 20,027 others like this.
Deleting a contact / conversation doesn't impact the other party's chat history. The conversations will be preserved on the other side whether you keep or delete. Blocking a contact means that person will not be able to chat with you anymore unless you unblock.
From the top of Chats or from the People tab, find the person you want to hide. Tap and hold on the person's photo or name. Tap Hide contact.
You can permanently unsend a message that you've sent or just hide a message from your view. If you select Unsend for You, other people in the chat will still see the messages in their chat screen. If you select Unsend for Everyone, people included in the chat won't be able to see the unsent message.
You cannot tell if someone deletes the messages on their Messenger. Your message will not be affected or deleted, nor will you be notified of what has happened. And if the case is reversed, you can request your deleted chat from the other person tosee your lost messages.
Find out more
A padlock icon is displayed next to the person's profile picture to tell you if a conversation is 'Secret'.
You only have to turn on the airplane mode of your device or shut down the internet. After that, you can read the message, and it will not show the read receipt to the sender. Note : The drawback is that the sender can see the read receipt whenever you turn on the internet or turn off the airplane mode.
Blocking Someone on Facebook Messenger
You can block them completely on all of Facebook. In this case, they will know you've blocked them because they will be unable to message you at all or even see your Facebook profile. However, you also have the option of blocking the person's messages, just on Facebook Messenger.
In a nutshell, the blocked person cannot contact you on Messenger and you cannot contact the blocked person on Messenger.
Blocking someone will have no affect on any data stored on your phone. The messages will not go anywhere unless you delete them.
Some of the reasons why you can't delete a message on Messenger include, you don't have the necessary permission, the site/app is experiencing some technical problems, or the sender has already deleted the message.