1997 Chevy Silverado fuel pump problems

About 2 years ago I started having problems with my truck starting. It was taking longer and longer and eventually one day it just wouldn't start. I had it towed and was told it was the fuel pump. I paid about $700 and was told the pump and sender were replaced. Now, its starting to do the exact same thing again. It's funny, it will start right up if its within an hour or so of me driving it, but the longer it sits the longer it takes to start. AND it will only start if I try it in short bursts about 5 to 10 seconds apart. What do you think? Was I ripped off? Surely a fuel pump should last more than 2 years.