missed calls

For the past several months, my iphone 8 + will not ring when a number, not saved in my contacts, calls me. I get a notification of a missed call and they are able to leave me a voice message. Now that I am working from home, my work phone is forwarded to my personal cell phone. I keep missing calls because the numbers calling my work phone are not in my contacts. I have searched everywhere online and it says my DND is on....It's not! They say power off your phone...I did! Is anyone else having this issue? Is this an Apple issue or should I contact my carrier?

Please help!