Widget callback for site

Good day! I am engaged in electric equipment not the first year, and I have an Internet shop. I often have to give advice to my client, but how to do it on the Internet? I was helped by a callback widget for the site. Very useful thing. When someone comes to your site and wants to get an answer to his question, he writes in a chat and at this time I receive a notification on my smartphone and I can answer the client video or audio call. This significantly raised my sales and brought my site to a new level! Recommend!