To delete contacts, you can make it by entering
their Profile page > click Delete contact.
Deleted contacts become strangers. If you still
receive their messages, you can click “ BLOCK”
on their chat to stop them from sending you
messages again.
Android phone users can click Block at the same
time while deleting contacts.
Tips:
1. The difference between deleting contacts and
blocking contacts is that after deletion, you still
can receive deleted contacts' messages, while
blocking will totally block them sending you
messages or call you.
2. After deletion and blocking, chat history will
be removed and they can't be retrieved. So you
are suggested think it twice before deletion, in
case of missing important messages.