How do I block or unblock a contact?
You can prevent a contact from sending you messages or calling you via WhatsApp by adding their phone number to your Blocked list. To learn more about the effects of blocking a contact, see this article.
On iPhone, there are a few ways to block a contact:
To block a contact that is not stored in your phone's address book, go to the chat for that person, tap on the number for that person at the top of the chat, and then tap Block Contact.
To block a contact that is stored in your phone's address book, go to WhatsApp > Settings > Account > Privacy > Blocked, then tap the Add New button.
When you receive an initial message from an unknown contact, you will have the option to Report Spam, then tap Report and Block. This will report the user and add the user to your Blocked list. If you receive an initial message from a known contact and want to block this person, you can just tap Block.
To unblock a contact, open the Blocked list with the above steps, slide your finger to the left on the contact you wish to unblock, then tap the Unblock button.
WhatsApp Support Team