Very great feature for a landline!!! Customer can text to the landline so you don't miss the business. This has been a game changer for my advertising firm. It helps me respond quicker to clients and provide better customer support to them. I have highly recommended this service to other colleagues.
Zipwhip - Zipwhip enables text messaging for landline, VoIP, and toll-free phone numbers.
Avochato - Text messaging for your business.
WikiPro - All-in-one Business to Customer Communication
Postscript - Like Mailchimp for SMS
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
GetChat.App - Add WhatsApp chat to your website for free