Problem displaying revenue value by categories

Hi guys, I have a kind of complex error, so if anyone has any idea on how to fix it, I would be pretty happy.

I'll try to explain it the best way I can.

I have two databases connected, one with customer accounts and the amount sold to them in a field called value. And another table with the clients evaluation of those accounts, the evaluation says if they're promoters, detractors, or passive clients.

I can display everything the way I want and it looks really good, but when I want to display the revenue by those NPS categories (dectractors, promoters, or passive) I get some problems. The problem is that a few customer accounts have more than 1 answer of NPS. So, when I display the revenue by NPS, and a few accounts have like one person that voted as a promoter, and other as a passive, for exemple, the amount of revenue in that account is being summed two times, on both categories, and in the end I have a big difference in revenue summing the revenue by NPS, and the general card where I display revenue.

I'll show the pic: