Download speed got lower

[Ulan]

So I did a speed test just before changing the wifi channel from 1(default) to 5 and the result was 200-400 Mb/s. After changing it it got lower to 60-80 Mb/s and it wouldn’t even go past 100. So I switched the channel back to its default but it’s still 60-85 Mb/s. What do I do? Please help. 

Edit: my plan is internet 600 btw

[mdk]

First, try the simple stuff: power-off your device, and disconnect the power from your cable-modem. Wait 30 seconds, and reconnect the power to the modem, and wait for it to finish restarting. Then, power-on your device, and rerun the Shaw SpeedTest.  Results?

Second, does your device have an Ethernet port? If so, use a "CAT-5E" (or "CAT-6") Ethernet cable to connect your device to your cable-modem, and rerun the speed-test. Results?

Third, telephone Shaw. They can remotely login to your cable-modem, and check its "incoming" signal-strength, and check other diagnostics inside the cable-modem.