We now have a Rural King shop and during the Black Friday sales they offered 10% off everything in the place. I got a soot eater for $42.83 or something like that, I may be wrong on the cents part. I tried it out on the chimney one day when I could let the fire go out and the chimney cooled down. I was not impressed. The soot eater did no better than the chimney cleaner I made myself for around $5.00; certainly less than $10.00. I took it back and got a refund. I was not impressed and if you want something similar to a soot eater on the cheap, I could share what I made in the DIY.
Is your string the right length? Did you use a drill to turn it around and around? Not sure how the soot eater did not clean your chimney....
The soot eater did not clean my chimney any better than the home made soot eater I built The only advantage would be that I have to screw my sections together instead of snapping them but that is minor. I purchased the soot eater because I thought the commercial one might do a better job but it didn't. I built mine using cpvc pipe and cpvc fittings. I forget what the cpvc pipe to drill connector was; something I located at Tractor Supply. I can't remember what I spent without looking at it and then adding up the prices; the fittings are usually as much as the 10 foot section of pipe. I posted this because you can make a soot eater clone that in my opinion (OPINION) works just as good as the ~$50.00 soot eater for very little in costs from parts available at Lowe's or Home Depot or Menards or ...
I have a couple of back to back offsets that could be 30 degree ones and they are on top of the stove. Would the sooteater rods be flexible to go thru them doing a bottom up cleaning? This is the only pic I have of them when they were first installed.