Some unknown callers coming through that unknown callers are blocked

In the three instances this happened they were businesses- legitimate, they are unknown as in not saved in my contacts- but when called through the phone rang instead of going to voicemail- I did not want anyone to ring through unless they are in my contacts- but all other calls were being blocked, I have not made emergency calls, and I have silenced unknown callers setting on and have turned off and on phone, software is up to date and turning off and on setting- is it where the business’s can pay a premium through something that allows to bypass this?