Set your Rogers modem to bridged mode. Buy a better AC router from Linksys / Asus etc. For the money TP-Link is good value.
x2. First, do not use the modems built in WiFi (you mention router, but don't mention a brand so not really an issue, but just saying for others) - get a good quality router (I'll second the TPLink, I use a Archer C2 and it's great bang for the buck) and put the modem into bridge mode. Ironically the modems built in WiFi sucks, and if you hookup a router to it without putting it into bridge mode the modem itself becomes a bottleneck.
The other thing to keep in mind is that not all AC connections are alike. Some routers, when running in mixed mode will slow down to the speed of the lowest speed connection....so for example, if there's an older device in your house that is only connecting to the router in G mode (vs N or AC) then
everything on that same network will also be forced to run at G speeds.
Anyhow, a good multiband mixed mode router (again, like the TP Link Archer series) do not suffer from this.
I have the Rogers Ignite 100 meg service and regularly see 120 megs over WiFi, with bursts up to 150+. This is basically the maximum of the connection, so I can saturate it to 100% without problems. This is over WiFi and only over an N (not even AC) connection as my Macbook I did this particular test on doesn't support AC.
My son has a TP Link AC adapter and can saturate the modem at 120-130 megs forever without issue.
Anyhow, I think the root of your problem is a crappy router (you didn't mention what make/model) and not having the modem in bridge mode.
First thing to try is getting the modem into bridge mode with your existing router and see if that helps. If it does, the modem was part of the problem. If it only helps a bit, your router is still suspect.
Secondly, login to the modem and lock the 5ghz band to only N or A mode vs any mixed mode options. Reboot it, connect with your laptop again, and see if that helps. If it does, then the mixed mode stepdown is your issue - in this case you can always limit your older hardware to the mixed 2.4ghz band and leave the 5ghz band locked at N or A as a workaround. This can and will prevent some older or incompatible hardware from connecting to the 5ghz band however. This, of course, all relies on the fact your router is configurable like this - some older/crappy routers may not be, in which case, consider upgrading.