Anyone else have issues with the Cingular 750 and calls cutting out? I'm not referring to dropped calls, but periods where the other side doesn't hear me. I've been using this phone for a couple weeks now, and almost every call has the other person saying "hello, hello" at some point in the conversation because they think we've been cut off. This is unlike any other phone I've used, so I have to believe it's an issue with the 750 I'm using.