iPhone user here,

I’ve checked my phone settings and I don’t believe this is happening due to my iPhone so I’m asking Koodo members for help! 
When someone unknown or a number that has never called me before tries to call me, they are prompted to press a number before being able to connect to a call. 
Why would this be happening? I’ve missed very important calls due to people being confused about the prompt to connect to a cell phone number, I’m hoping I can have some help on fixing this without having to wait on hold with Koodo customer service. 

I really appreciate the time