Tuning Huma-Air Extended Scope Rail With Barrel Stiffener And Tensioner Kit

I received one in Arizona within a few days. Unfortunately, it didn't fit my M3 without changing parts. It's now for sale in the classified section.
What parts do you need to change? I received one as well and the two rear mounting screws are off about 1/2 a hole width. Did you ask about returning it for a refund?