I have 2 contacts that their numbers are showing on red and when they call me it goes straight to voice mail but i looked the configurations and their are not block

Make sure they are unblocked for your Phone, FaceTime, and Messages. See the "Manage your blocked phone numbers and contacts" section in:

Block phone numbers and contacts on your iPhone, iPad or iPod Touch - Apple Support

Also, is it possible you have a third-party app that is blocking the contact(s):

Detect and block spam phone calls with third-party apps - Apple Support

They may not be Blocked but they may be set to Do-Not-Disturb. Check your contact entries again.