Did you get a letter that looks like this in the mail?
If you didn’t, either you are not an Acton Eversource customer, or you chose an electricity supplier some time ago that isn’t Eversource. If you don’t remember getting this letter, but you want to participate in Acton Power Choice, get a recent electric bill so you can have your customer number ready and call Acton Power Choice customer support at 1-844-379-9933 and they can get you sorted out.
Here’s what the letter inside looked like (click for a larger version)
Here’s the official Acton Power Choice letter of August 2017