I purchased a 510 vape-O-Matic Liquinator 8.5mL BFT from vaporescence in Texas, they come with dual coil carto's, it burns hot and spits, bad taste and it is awful, I called the store, talked to the owner about the problem, he told me the dual coils don't work well, but did not have an answer for me, except to but another with 5.5 Ml. and to install a single coil carto, and that should work better,But in the mean time he would not offer an exchange or give me any credit, It's my problem he told me. The tank has not be used but only to try it out. What a great store to do business with. Any Ideas ???