Customer support tickets arrive and are answered here.
A reply and an internal note are not the same
Anything written in the reply box goes to the customer, unless you mark it as an internal note.
An internal note appears in the same conversation alongside every other message, but the customer never sees it. Because both are written in the same place, it is worth glancing at that checkbox before sending.
You may not be seeing every ticket
A user without full access sees only tickets assigned to them — and the counters at the top of the page count the same way.
So two people opening the same page and seeing different totals is normal, and "the ticket disappeared" usually means it was reassigned.
A customer reply does not change the status
A ticket has five states: open, in progress, waiting on customer, resolved and closed.
If a customer replies to a ticket that is resolved or closed, the status stays exactly where it was. Their reply is recorded and every admin gets a notification, but the ticket does not reopen itself.
The practical consequence: if you are filtering to open tickets, that reply is not in your list. Treat the notification as the signal, or set the status back to open yourself.
Tickets are not deleted
There is no way to delete a ticket. One that is no longer needed is closed; its history stays.
The change log
Every status change, assignment and reply is recorded in the change log. When it is unclear who did what and when, that is where the answer is.
Linking to a guide
While writing a reply you can search the product help and insert a link to an article instead of retyping the same explanation. The link points at the public guide, so it stays current.