Why Do Blocked Numbers Still Ring on My iPhone?

If you have added a contact to your block list using the steps here: Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch, then it is possible the caller is using a third party source to get their call to come through.

Why is a blocked number still calling me on iPhone?

Ensure that their Apple ID is blocked too.

Some spammers may spoof the Caller ID. It is possible that they are not calling from a real number. If they are disguising their identity by falsifying the caller ID information, this is called caller ID spoofing. Read this Apple documentation to handle these types of calls.

Why do blocked numbers still ring through?

The problem is there, the block calls feature is tricked, in reality it sees 555-1234 even though you see 555-7890. So even if that is blocked it will still ring because it sees the real number and NOT the one that shows (blocked) on your phone.