Am i getting screwed by the dealer?

West Herr ford’s service department blows. After I bought my car used from them I noticed my battery light was going off at around 5.5k rpm’s. I figured it was the alt because this had happened to another car i had owned. Sure enough it was and It was still under warrantee so I took it in and they replaced it. They replaced it with a bad alt but the battery light still went off but this time it went off closer to 7k rpm’s. A few months later it got worse so I took it back to West Herr. They basically told me that I didn’t need to get my rpm’s up that high and they would not replace it again. From personal experience, I can understand how they are dicking you around.