So I just got a maraxus clone by EHPRO, from my local vape shop exactly one week ago. Its already not working, even with a fully charged battery. it will barely hit sometimes, and then the majority of the time, not at all. Im using a tobh on top, and a sony vtc 5 18650. it cant be the battery because ive used two different of the same type that were working fine. On the bottom contact where the bottom of the battery sits, there is some sort of oxidation on it. Ive tried tightening everything down, loosening everything, etc. Will cleaning the contacts do the trick? if not, what can i do to fix it? or do i have a dud and need to return it?