I have approached a well known law firm about suing Hydro One (at least) in a class action suit. If I, and anyone else, can get enough evidence together they are interested in pursuing this.
If we can get this going it could be the largest lawsuit in Ontario's history. Do the math. Assuming for every 1000 people who got over charged $100 for one month, that's $100,000 for one month. Multiply that by the percent more than $100 (mine was $300 more for Feb alone) times 12, times how many over 1000 people affected, and this could be in the hundreds of millions.
If you want to join in the class action please contact me at email@example.com.