From list of suggestions at:

https://twitter.com/JKjaersgaard/status/1486206991030759424

Also see:

How to Build an Effective and Friendly App Support Process

Outsourced Support

Customer Support for your Shopify Apps - The Support Heroes

https://twitter.com/DsMatie/status/1544276455328075776?s=03

Odys Media

Chat

Tawk: FREE Live Chat • Ticketing • Knowledge Base • Chat Pages • Team Chat • + More

100% FREE Live Chat Software, Ticketing & Knowledge Base! - www.tawk.to

ChatWoot

Chatwoot: Open-source, self-hosted customer engagement platform, opensource alternative to Intercom, Zendesk