Q: Why are blocked phone numbers still ringing on my iPhone 6?

It's generally impossible to answer "why" questions here, as we do not have all the facts.

Review the blocking procedure, and make sure you did it correctly.  Report specifics back here if you have questions.

Block calls and block or filter messages on your iPhone, iPad, or iPod touch - Apple Support

Have you confirmed that the calls are. Owing from the same number? Marketers are good at spoofing different numbers.

You can also try blocking the number at your provider's website, so the call never reaches your phone.

I Have the same question. I've searched the forums and there are dozens of people with the same question and all anyone seems to be able to suggest is that we aren't blocking properly. Sigh. The procedure hasn't suddenly changed. In my case specifically, I keep a contact on my phone called spam. It is blocked. Whenever I get a spam caller I simply add them to this contact and  don't have to worry about them. But I have a record of who they are. I've been doing this for years and there are probably hundreds of numbers in this contact. It is only recently that I am having problems with calls ringing through. They are numbers assigned to that contact. So I'm wondering if something has changed on iPhone's end or if I've reached a contact max or need to do some sort of reset. Reporting all of these numbers to my carrier to shut them off there is a bit extreme when some of these numbers were blocked nearly ten years ago and arent likely even a problem any more. As a control I blocked a friend and had her call and she went straight to my VM. Never rang or showed up on my end at all. So I suspect the problem is with this specific contact, I just don't know if it's something with a solution.

You can try to create a "spam2" contact. It is possible that there is a limit per contact