Family Dollar — Return and very rude

I had bought a cell phone the night before. It wouldn’t activate and I know how returns are on them in most stores. I looked up the return policy and it said if I had my receipt they would exchange for the same one. That’s what the Verizon huh told me to do. I went there and she said they don’t do that. Well if it’s the return policy how can they deny me? It was never activated and I had just purchased it the night before. I thought one return policy was for all family dollar stores and if that’s so I don’t see how she could refuse my request. Seems like some employees just like to make their own rules up.