Eversource overcharged me for years, anyone else deal with this?

So I just found out that Eversource never enrolled us in their heat pump electric rate. We built out home in 2021 and were told by Eversource, Mass Save, and our heat pump installers that we would automatically be enrolled in Eversource's discounted rate program becuase we installed high efficiency heat pumps.

After talking with a friend and complaining about extreme electric bills I looked over our account and discovered we were never enrolled in the program and therefore have been overpaying for years.

I've gone through the process of submitting the appropriate documents to enroll in the program now. We should be enrolled by next billing cycle.

Has anyone been able to be reimbursed for the same problem? If not, any idea how we could go about making a claim or an appeal? I'm so mad at everyone including myself for not catching this sooner. Our house is less than 1000 square feet and built to 'reach' standards higher than the state requires yet we still end up with electric bills over $800 every winter.

A big thanks to anyone that has insight, and a hug to anyone who has dealt with the same issue.