Then post some pics of your issues. If they provided exactly what you needed, then there shouldn't be any issue?
So I had my rims drilled to spec before I knew the fronts were hub centric. So I need 5x5 half inch hub centric spacers to fit and longer studs which I have already.You need to explain EXACTLY your issue.
The stock impala is hubcentric front and rear with about a 3.063 dia register
Many aftermarket replacement axles are either so short on the register that they dont engage the rear rim or they are the smaller F or Y body 2.768 dia.
Your adapters front and rear should have a hole on the car side that is 3.063 ish and a stub on the wheel side that is 2.768 ish