Dynamic drivers are usually the ones that change with burn in. You probably just don't like the sound signature and in that case it's unfortunate. The biggest part of choosing a custom is choosing one that suits your actual listening preferences.
Maybe if you talk to them, they can give you an idea of which of their line-up may suit you better. Maybe even in an extreme case they'll redo your iem and give you a different model. I wouldn't really expect that but who knows?