Telus Call Back feature does not work on my iOS cell phone either. Call back goes straight to voicemail. No ringing. Not shown as a missed call either. It hasn't worked with call backs from any department with Telus for a few years now. I've complained, and still it does not work. Have to use landline for call backs to reach me. Telus needs to fix this asap. Not everyone has a landline.
Call control is available for mobile as well. I've hyperlinked an article about Call Control for mobile in my previous post which walks you through how to manage it (and check to see if it's enabled on your line).
For what it's worth, I have Call Control enabled on all my lines. Whenever I receive a callback from TELUS, it's successfully passed-through Call Control with a Result of something like globally accepted/allowed.
I have the number that shows on the CID saved in my contacts. I've had no issue with callbacks previously. However, I was supposed to receive a callback Saturday morning that I didn't think was even attempted as my phone didn't ring.
Later, I noticed in the call logs that there were a few calls, but they're marked as "Blocked by Phone" though. I have a Samsung Galaxy Z Flip4, and assume that Hiya is blocking TELUS as a spam call, even though it's saved in my contacts.