I had that happen with HTC. I've called their support line before, and they were fine, but this time, we determined that my phone had a major issue. Their solution? Send it in for a repair and we'll send it back to you in 10 days. I told them that was unacceptable, hung up, and called AT&T, since I bought the phone directly from them. AT&T did some troubleshooting, and then said, "Yes, we will replace your phone." They were much better. I think if it's a minor issue, I'll call HTC from now on, but AT&T will get the warranty calls. Interestingly, they could replace it themselves with no contact with HTC.
I'd recommend you take your phone to the Apple store, though. If it needs to be replaced, they can do it more easily there. We had my mom's iPad replaced, and they were very good in the store about that.