I booked an appointment and never heard back.

My appointment was not confirmed immediately, and I never received confirmation via text or email. Why not?

If your appointment wasn't approved immediately, this means that someone on the seller side (either the listing agent or the seller) must manually confirm every requested appointment time. Any time an appointment is requested, we notify the approving party about the request, with the tools they'll need to approve, reject, or reschedule the appointment.
For whatever reason, the agent and/or seller didn't act on your appointment request, and left the appointment status as Pending. In a perfect world, they would have opted to cancel if this was a bad time, or request to reschedule, but they didn't.
You are welcome to contact the agent directly to see if a mistake was made, or in an attempt to speed up the process. 
If you have other questions, please let us know!