See Contact Details in Chat
The first thing you should do is open a conversation in the WhatsApp application for iPhone or Android and then look at the contact details at the top. If you can’t see their profile picture and their last seen, it’s possible that they have blocked you.
The lack of an avatar and last seen message isn’t a guarantee that they’ve blocked you. Your contact could have just disabled their Last Seen activity.
RELATED: How to Hide Your Online Status in WhatsApp
Try Texting or Calling
When you send a message to somehow who has blocked you, the delivery receipt will only show one checkmark. Your messages won’t actually reach the contact’s WhatsApp.
If you messaged them before they blocked you, you would see two blue checkmarks instead.
You can also try calling them. If your call doesn’t go through, it means you might have been blocked. WhatsApp will actually place the call for you, and you’ll hear it ring, but no one will pick up on the other end.
Try Adding Them to a Group
This step will give you the surest sign. Try to create a new group in WhatsApp and include the contact in the group. If WhatsApp tells you that the app couldn’t add the person to the group, it means that they have blocked you.
If you’re annoyed, you can block someone back on WhatsApp quite easily.
