Garbage internet for the past while

For the past month or so my internet have been abosutely terrible. To a point where I use my mobile data rather then the wifi in my own house right beside my setup!

One of my computers are in my room across the apartment, which I even have an extended wifi dongle attached to and it still is slow as all hell.

I've disconnected and reconnected the router, set it back to factory settings, moved it, I've done everything and it's still hardly working. Every device I own takes forever to connect, it drops constantly and when connected are very slow.

I've been a customer for almost ten years at Videotron and never had issues like this but the past month has just been garbage. I don't even want to pay for your services anymore. 

Is anyone else having the same issue? I'm going to change providors if something isn't done...I shouldn't have to buy accessories just to connect to my internet...