Hi, SimplySag!
Thanks for dropping by the Apple Support Communities. After reading your post, we understand you're not able to receive calls on your iPhone. Callers get a message indicating you are not accepting calls. We're happy to help!
We're happy to see you've checked the Do Not Disturb settings and Blocked Callers list. While these features would prevent your phone from ringing when someone calls under specific circumstances, it would just send those calls directly to voicemail. There would be no other indication to the person calling that you were unavailable.
To find out why this may be happening, then, we recommend using the steps in the article you came to the communities from, If you can't make or receive calls on your iPhone - Apple Support, if you haven't already.
Should the issue continue after going through those steps, we suggest getting in touch with your carrier: Wireless carrier support and features for iPhone in the United States and Canada - Apple Support. They provide your phone's service, and handle call routing. There may be something on their end that needs to be addressed.
For additional assistance after that, please get in touch with Apple Support directly: Get Support.
Best!