Did you tried basic troubleshooting?
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Yes. And despite not having sent a message, somehow a ticket was created. When I go to the site and interact with that ticket to provide additional info/communication, I get an email saying that I responded to an email that isn't monitored (even though I made the response IN Upwork). So it seems Zendesk isn't managing things very well for you (see screenshot).
Thank you for the detail report. Our team will investigate this further and will contact you soon with more details via ticket.
If you encounter any problems on your end feel free to ping me here or send me a PM.