I've seen issues with the app saying the modem is offline when obviously it's not. It seems to clear itself up after some time.
Is your slow connection over a wired or wireless connection? Have you run a speed test from the Telus My Wi-Fi app? This will give you speeds from the Internet to your modem. If you are not getting speeds near what your plan states in the the My Wi-Fi app you should contact Telus.
If it's wireless speeds there are many factors than can affect that.