I'm sorry I have very little knowledge about SMS and MMS messages and how they work, especially with Telus, and with apologies to ehMac.ca, I don't think there are many members here who actually use Telus, so I would suggest you try various Google searches and/or the Telus forums support starting with something like this:
And then there's their support site:

Forums
Bring your questions, comments, and learn something new about TELUS products and services. Join the conversation!
I'm not exactly sure, but I think you may have to set up your Messages.app preferences using your Apple iCloud account on your Mac, but I'm not 100% sure about that.
But hopefully some experienced expert will reply here with a proper solution.
- Patrick
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