Unannounced rate hike and bill after cancellation

Well, where shall I start? My internet bill used to be 50 dollars and last year it randomly jumped to 75 with no notification. In addition, I found out Telus kept charging me for security camera for THREE years after I no longer used it.

The truly audacious part is that, after I cancelled my account, I was hit with another bill of close to $100 for a period where my usage of their service is absolutely ZERO and with the modem returned. 

Having been using Telus for years, this makes me not wanting to return to it at all.