This is a known problem with Android versions higher than Android 5.0 Marshmallow. If Avon Dialer is installed, long tap on it and then go to App Info. Scroll down to the Permissions section. Tap on the Contacts and enable all the ones that you need and then restart the software. It should have access to the Contacts now. If you install other applications, the same procedure needs to be followed as well to enable access in case the software doesn't set them properly.