got a facetime call from unknown Gmail id.

I thought Apple devices were safe until I got a call from an unknown Gmail id. I was shocked a lot. I never share my contact details with unknown persons. Any option to "select receiving calls from contacts" for facetime calls only?

Messages and phone calls are okay to handle with unknown persons but a video call is scary. Sometimes when we are in hurry, we will lift a video call as an audio call. Apple should concentrate on this part.

I saw on the internet, there is a feature for blocking particular calls in the facetime app that is not a solution. If we block that call that scammer will call with another ID. Please help if I miss any option to resolve my issue.