CRM add on app for sms text messaging to contacts one to one

CRM add on app for sms text messaging to contacts one to one

Has anyone been able to get the twillio sms add on to work? I would live to send text messages to prospects and customers in zoho but I am unable to get the add on to show up on the contact or lead pages.

There are several sms add ons in the market place -  some appear to be out of business. 

So I was wondering if anyone has success sending sms via zoho in any way?

Thank You