When the on/sleep switch went on my ancient iPhone 3G, I thought the phone might be toast. That's what happened to my last one... repaired by some other joint. These guys fixed it overnight... and it was fine for a day or so. But then I realized the ringer switch didn't work (the ringer was permanently off) and the sleep switch still wasn't working right. It was a couple of weeks before I was able to get back there. They re-did the repair immediately, while I waited, at no charge. The phone now works perfectly - or at least as well as a 3G can.
That's customer service and taking responsibility.