Someone at Public Mobile / Telus needs to be reminded that they only offer 3G data, (with no customer service call center). All plans rates should be at least cut in half or start offering 4G/ LTE or even 5G. As mentioned in previous comments, why ...
@Jinjangbesi Your messaging app is different from the dialer app. But for some reason, your dialer app has default permissions to send sms messages. So you are blocking sms permission on the dialer app only. Don't block sms on your messaging app.
I can confirm that blocking the phone app SMS permissions does work, but it is still concerning that the phone / OS is sending texts in the background. I am a little suspicious because this 7723 number seems unique to Public Mobile.