Try overdoze ampang. I saw it in their shop recently.

Ohm jumps due to coil not intact properly with screws. Or there is some junk stuck inside or in between. Best is take of everything including screws, clean with warm water. clean anything that doesnt belong there. Also when doing the build, make sure the coil is not that wide or high until it touch the chimney,
vapingbuddy sri petaling got last week when i visitted them. But sleeve looks pointless as u have to take it out in order to take out battery to charge em.