The ceramic shouldn't "foul out" and become nonfunctional, unless you tried ABV ISO oil or something... even then it shouldn't be permanent. Put it this way, I put the AVA (built for actually viscous liquid e-cig juice) through that CO2 oil, regular hash, bubble hash, and then a cleaning or two later went straight back to e-juice and to this day it's worked as well as it did with e-juice the first day.
The DART's been a dream since the second I used it till now. Wax, oil, honeycomb, does it all. How long do you warm it for when you add a bit of oil in? I usually do 10-15 seconds from placing the dabber back on before I start drawing, but I'm also using the 3.7v LR DART so I think it's a few seconds longer of initial warm-up time before I start seeing nice hits. Like you can see in the vid, the first hit I get is a bit on the "whispier" side but the second and third go straight to the dome. My understanding re: construction is that there's a donut ceramic wafer inside, but you can't see it because the heating core is in the middle of it, and the top wafer that you can see blocks out about 90% of the view. Add your wax, let it melt through the ceramic, hit it, second hit is faster/easier because the concentrate has melted into the donut, and also because of retained heat.
AW is a brand of batteries, stands for Andrew Wong I believe (might be the guy that pioneered the tech or maybe just a line of batteries?) Are you using the green Tenergy ones, or are they black wrapped?
If bad goes to worse for you... TV doesn't make Revolution kits anymore. DART carts just by themselves fetch $80-100 (totaled at ~$65 new?) so I don't think it would be too hard to sell it on the Classified's here if you wanted to see some (most if not all) of your money back...