The old free extension has depreciated. Now we have two professional chat buttons:
1) Lucknowwebs Chato (Live chat support) Extension
2) Social Live Chat support extension for webbuilder 14, 15 and above

Details here:
http://lucknowwebs.com/lucknowwebs-chat ... -extension
http://lucknowwebs.com/social-live-chat ... -and-above