Just eco savings review: Rebate Scam and charge for cancellation

Just eco sales came to my door in 2013 and he mentioned that it is a of government program related to hydro One smart meter to upgrading the thermostat to the new smart programming thermostat system.
He mentioned it will save us average around 25% of our electronic bill which is up to 400 per year.
Instead we will pay bill 14.96 / per month. If we did not save 14.95 / per month, they will rebate us, just eco saving has system to calculated and compare it. He also told us that there is a guaranteed rebate program, so that even in the event that you save less than the cost of the program, the difference will be rebated back to you. Therefore, I got the feeling it is no risk program at all and it is government recommended.

But after two years use, from the bill i don't feel that is much saving and I have never received any rebate, only monthly charge from just eco saving which is increased every year on Enbridge bill. So i called them to ask rebate, the truth is they did not give you back the entire amount I spent and all the months too. I don't know how they calculated, I asked why only get partial of month in a year and max $10 instead of $14.95 I spend, they mentioned that I did not properly used. I asked them to give me the definition of properly use the themestar means. I called several times and email twice, nobody give me a clearly response.
So I was so tired of calling and email them, so I ask to cancel the service. But they charge me $135 plus GST for cancellation, I called them and emails them several times again, I told them I can take the themestar out and delivery to their office, but they say no.
I took my lesson for this, never believe the sales which come to your door and make so many wrong statement, there is no risk free thing. Never trust Just eco saving this company, it is real bad experience to deal with their customer reps.