You may want to consider just how you ring an answering service. We've done this in the past and will be doing it again this year. While it doesn't completely alleviate any customers contacting you on your personal phone it does dramatically cut it down. And then you can also direct them to your business line.
I use Google Voice. Alternate phone number, same device. Allows you to set up a voicemail for it, and you can disable it during certain hours so all calls go to voicemail. It's free and easy. I do save clients into my contacts.