I'd recommend that you send the pedal in for service. Whether or not you use it in the effects loop or in front of the amp isn't the issue, that's a personal choice. It works better for some people in some situations, but isn't a requirement. If I had to guess, the rep who told you to try it in the loop was just trying to determine where the problem was and not suggesting that the pedal *has* to be used in the loop.
