helprealm.io is a free SaaS support ticket system and helpdesk for freelancers and small teams.
It provides you with a support contact form that can be linked on your website (or embedded via an iframe). By using that contact form your customers can submit support requests which can then be processed by you and your agents.
Customers can reply to tickets via the support thread form or by replying to e-mails.
The product is completely free of charge / free of ads.