I had this issue a couple weeks ago. I have 1.5gbs fibre and was getting speeds are 300mbs on wifi so I performed a manual factory reset on the wifi hub. After the reset, I could no longer perform a speed test through the telus wifi app as it said the device was offline. Spoke to a couple reps with no success and I had a tech come by but didn't do much to resolve the speed issues and the new issue of not being able to run a speed test.
The solution that worked for me and got everything back to normal was to sign into Mytelus and change my internet plan from 1.5gbs to 1gbs, then after 10min or so, switch my plan again back to 1.5gbs. Then I re-installed the telus wifi app, registered the wifi hub again, and ta-da! Just a theory and not certain if my little workaround actually did anything, but may be worth a shot!