i posted that coupon number given, in an earlier but now locked thread, in the comment box on the njoy site and they sent me an invoice but the coupon took off only 10%. should it be 20%? also i was wondering if the cartridges sold on e-cig are compatible with the njoy cigartette? im planning on buying them and the e-liquid from e-cig as it was mentioned on this forum this is the cheaper alternative to buying the pre-filled cartridges.