Nevermind i know the issue now, i knew i remember reading about what was going on with your stuff. Okay, so here goes, they don't have peewee parts in stock anymore, i don't know if they have a stash or what, but the RN4081 model burns through atomizers like fat kids through cake (sorry if that offends anyone). I keep a stockpile of 20-30, and am about to switch to a different e-cig all together. Keep in mind, i am a really heavy vaper, so others may say that there atomizers last forever, or whatever. I know the burning thing you are talking about, it just happens with some of them, probably a bad solder joint, well nvmd, but yeah it happens.
Be patient, this industry is still pretty new, the RN 4081 is the smallest e-cig ( i think) made, or one of the smallest. With being the smallest, you have a higher failure rate than your bigger brethren. If you were past the 14 day warranty before contacting them, then all you are going to get is polite explanations of what probably happened to your HW. If you were within the 14 day warranty (which is about how long i get out of an atomizer, but thats because i abuse the you know what out of them), then i am sure someone will help you.
There are some places with it in stock if you, i won't mention names, but will point you to , go there, and you will see a listing of the different models that are compatible with the 4081 parts,, of what suppliers carry it, with the corresponding product names.
edited to correct link to the e-cig wiki
Hope that helps.
Gibby