You need to call and get someone else. Others have done just the band exchange. They add the band online to your original order, and email you a return label for the band only. You can keep your old band until the new one comes and then mail the old one back.
I personally spoke to a rep yesterday b.c I was contemplating doing this and wanted details. The above is how they described the process. Also, I am outside my 14 days and they were willing to still exchange the band only. I do not know if that is only b.c I was "upgrading" to a more expensive band.
The problem with this approach is that the Modern Buckle is not available to order separately at this time. I do agree that the poster needs to call again and be persistent however.