A staff member didn't get the text about their shift

The most likely reason is that the week has not been published since the shift was added or changed: nothing is sent until you publish. The shift is on their My shifts page either way once it is published. The reasons, most likely first:

1. It has not been published. On the Weekly roster, a shift that says Draft — not published or Edited — not republished has not been sent. If the publish button shows a number, such as Publish 3 changes, press it. See Publish the week's roster.
2. They did not choose SMS. On Club › > Staff Roster › > Bar & events staff, Notified by shows Email, SMS or Email + SMS. Staff can change this themselves once they have signed in. The publish dialog shows each person's chips before anything is sent.
3. There is no mobile, or it is wrong. The publish dialog shows No mobile for someone with none. A wrong number shows SMS failed when you publish, with the reason. Correct it on their staff record, then press Send it again on the shift's panel or in the publish dialog.
4. The text failed. Press Notifications on the Weekly roster. Under Sent, find their message: Failed gives the reason, Switched off means SMS was off at the time.
5. They are inactive. The publish dialog shows Inactive: not told. Tick Active — can be rostered on their record if they should be rostered.
6. The text was for something else. Cancellations and changes to a published shift are told only at the next publish, in that week's one message. Reminders go between 8am and 9pm only, once per shift.

Staff answer a text with the link in it, or on My shifts, not by replying. To send someone their unanswered shifts again, choose Send it to them again from their shift's menu.